1) Assassin's Blade. This skill is a melee ranged execute, dealing a low amount of damage to high health enemies and a massive amount of damage to enemies below 25% health. The execute damage of this skill is so high, that it is sufficient to kill a low health blocking target with 1 button press.

Morphs:
Impale - This morph adds range to the execute, making it usable from up to 19m away from the target, instead of the usual 5m range. This attack is still considered as a "Melee" attack by the game engine, so it is unable to be reflected and the Sword and Shield (SnS) passive "Deflect Bolts" is useless.

Killer's Blade - This morph switches the scaling of the skill to stamina and weapon damage, as well as adding a heal that activates when you kill a target with this ability, healing you for 20% of your maximum health. This morph gives stamina based Nightblades a usable class based execute.


2) Teleport Strike. This skill teleports the Nightblade in question behind the target, then slashes the target, dealing damage. This skill benefits is unique among gap closers that it benefits from the sneak attack bonus as well as not requiring pathing to perform. The sneak attack bonus this skill received is classed as a "Melee" type sneak attack, so it will have a higher multiplier then a ranged sneak attack like a stealthed Snipe.

Morphs:
Ambush - This morph switches the scaling of the skill to stamina and weapon damage, as well as providing an Empower buff when activated. Empower increases the damage of the next ability used by 20%.

Lotus Fan - In addition to the direct damage of the teleport strike, this morph adds an AoE that deals damage and inflicts a bleed, snaring enemies affected by the bleed. The AoE pulls targets affected out of cloak, and the snare effect provided is invaluable in chasing down enemies. This is especially potent in the cramped hallways and alleys of the Imperial City.


3) Blur. This skill grants the caster Major Evasion, which means that the caster has a 20% chance to dodge incoming attacks. The 20% chance may seem low, but it's significant in helping you avoid damage as a Nightblade.

Morphs:
Mirage - In addition to granting Major Evasion, this ability now grants Minor Resolve and Ward, increasing the caster's armor and spell resist by a small amount. This is one of the few sources to obtain Minor Resolve and Minor Ward available in the game.

Double Take - This morph grants 4 seconds of Major Expedition to the caster on activation, granting 40% extra movement speed, allowing this morph to be an excellent mobility skill to have. This is the one of the only two sources for Major Expedition in stealth, the other being a speed potion.


4) Mark Target. This skill marks an enemy for death, inflicting Major Fracture and Major Breach on the target, massively reducing both armor and spell resistance. This ability can be cast from stealth without revealing oneself, but the visual effect of the ability is very distinct, and casting this on any decent opponent in PvP will result in the opponent immediately entering defensive mode, putting up Wards, Block, Dodgeroll, Bolting away. You can mitigate this issue by casting it just before the stealthed attack lands, as then the target will have no time to respond to being marked. If the target is killed while under this effect, you are healed for 40% of your maximum HP.

Morphs:
Piercing Mark - This morph ensures that even if the target were to stealth or to go invisible, you'll always be able to see him/her. This morph also negates the "miss" mechanic of Dark Cloak, allowing projectile attacks to hit a cloaking target without missing. With the fixing of cloak in the Imperial City update, this skill becomes even more important in tracking and hunting down Magicka Nightblades.

Reaper's Mark - This morph increases the heal given by this ability to 60%, as well as granting Major Berserk after killing the marked target, increasing your damage by 25% for 5 seconds. This is one of the few sources in the game for Major Berserk.


5) Grim Focus. A rather unique skill, this skill's base effect is to grant Minor Berserk, increasing damage done by 8% for the duration of the skill. However, after you perform 4 light or heavy attacks with this skill active, this skill changes into Assassin's Will, allowing a free activation to summon a spectral bow, which deals massive magic damage to a single target. The damage Assassin's Will outputs far outclasses most ultimates.

Morphs:
Relentless Focus - This morph grants Minor Endurance in addition to Minor Berserk, increasing stamina regeneration by 10% for the duration of this skill.

Merciless Resolve - This morph increases the damage done by Assassin's Will, as well as adding a snare effect to targets hit by Assassin's Will, snaring them for 40%.


Ultimate: Death Stroke. This cheap ultimate deals massive damage to a single target, as well as inflicting a unique debuff that increases damage done to the victim by 20% for 6 seconds. Also inflicts Major Defile, reducing healing taken by 30% for 6 seconds.

Morphs:
Incapacitating Strike - This morph adds a stun effect to the ultimate, stunning the target for 4.5 seconds if the caster has lower health then the target when the ultimate was activated.

Soul Harvest - This morph grants the Nightblade an additional 10 ultimate per kill while this ability is slotted, ensuring that this ultimate will be ready earlier and more frequently.

1) Shadow Cloak. Best explained by my other guide on Cloak mechanics, the link to the guide is here.


2) Veiled Strike. This ability is the bread-and-butter of most melee nightblade builds, and it's one of the best abilities in the game. It's a cheap spammable melee range nuke that also has a near instant animation, which makes animation canceling a breeze. The ability also imposes a 4.5 second stun + off balance when used on a target from stealth, allowing 15% bonus damage to the target with a fully maxed out Ruffian passive (Dual Wield). The stun can be CC-broken, but the off balance can not be CC-broken. It's morphs make this skill even better.

Morphs:
Surprise Attack - Changes the scaling of this skill to stamina and weapon damage, this morph is the cornerstone of a good melee stamina nightblade build. In addition to the base version's stun + off balance from stealth, this ability inflicts Major Fracture, lowering the target's armour by a massive amount for 12 seconds. Use it on a light armor wearer, and they might as well be wearing nothing at all.

Concealed Weapon - This morph increases the speed of the Nightblade's sneak by 25%. Couple with Dark Stalker (Vampire Passive), Major Expedition and this to obtain mount-like speeds while in stealth or invisible.


3) Path of Darkness. The idea of the base skill was good, but the execution failed to meet expectations of most Nightblades, especially after the Major/Minor buffs system gutted the ability. This ability creates a tiny area of darkness where the casting Nightblade gains Major Expedition while standing on the path, as well as dealing minor damage to enemies standing on the path.

Morphs:
Refreshing Path - This morph adds a small HoT to the any ally who stands on the path. Mainly useful for tanky nightblades who prefer to stand their ground, but even then, there are better skills to put on the skillbar.

Twisting Path - This morph increases the radius of the path by a small amount, in addition to dealing slightly more damage.


4) Aspect of Terror. A signature skill of the Nightblade, this skill inflicts fear on up to 3 nearby enemies, causing them to run in terror from the caster for 3 seconds. This ability bypasses dodgeroll and block, making it ideal for dealing with permablocking or permadodging opponents.

Morphs:
Mass Hysteria - Adds a snare and a maim to the skill, causing enemies affected by this skill to be snared for 50% as well as dealing 15% less damage after the ability wears off or is broken out of.

Manifestation of Terror - Changes how the skill functions. Instead of fearing nearby enemies, you drop a trap on the ground that takes 3 seconds to arm. Once armed, any enemy who steps into the trap's activation radius triggers the trap. Once triggered, it instantly fears all enemies within a 10m radius of the epicentre of the trap for 4 seconds, bypassing the previous 3 enemy restriction of the base version. This morph allows for whole raids in Cyrodiil to be feared at the same time, should one of their number step into the trap, due to the current meta of stacking on the crown. The trap lasts 30 seconds after being deployed.


5) Summon Shade. This skill summons a invulnerable shadow armed with a pair of daggers to rush at an enemy, slicing the target with it's daggers, and dealing 4% of your max magicka as damage to the target per hit. Enemies hit by the shade's attacks deal 15% less damage due to Minor Maim. This ability can be used to drain a blocking target's stamina.

Morphs:
Dark Shades - Summon an additional shadow to rush at enemies, meaning two shades will be summoned instead of just one. The stamina drain benefit is extremely punishing on an opponent's stamina, as stamina no longer regenerates while blocking, and thus any stamina lost is not easily recovered.

Shadow Image - Changes how the ability functions, the shade will now be armed with a bow and deal 6% of max magicka per hit. The shade is now immobile, but you gain the ability to teleport once to the closest friendly shade. This means that you can teleport to an ally's shade, if the shade in question is closer then your own. This ability can be used to elude whole armies in Cyrodiil, making them chase you on a wild goose chase before vanishing to teleport back to your shade.


Ultimate: Consuming Darkness. This ultimate conjures a circle of shadows in a 5m radius, protecting the caster and any allies who stand within the circle of shadows, reducing damage taken by 30%. Enemies who step into the circle are snared by 70%. Allies within the circle are granted a synergy that renders them invisible, increasing movement speed and healing them. This ultimate is best used in conjunction with another ally's ground targeted ultimate, a good example being Negate Magic and Dragonknight Standard.

Morphs:
Veil of Blades - This morph adds a damaging effect to enemies that dare trespass into the the circle, dealing moderate damage every 0.5 seconds so long as they are within the circle of shadows.

Bolstering Darkness - This morph doubles the effect of the damage reduction on the caster, increasing the reduction in damage to 60% so long as the caster stands within the circle of shadows. When combined with Reactive Armor (IC Tel-Var Armor set), the caster can literally take no damage while standing within his/her circle of shadows.

1) Strife. This skill sends a magical ball of energy at a target, and on impact, the ball of energy deals damage as well as triggering a secondary ball of energy to return to the caster. The secondary ball will then heal the caster for 25% of the damage dealt by the primary ball, every 2 seconds for 10 seconds, essentially healing for 125% of the damage done by the skill. This skill is notable for it's low casting cost, as well as moderately high damage, allowing magicka-focused Nightblades to use this a primary means of dealing damage at range.

Morphs:
Swallow Soul - This morph provides a passive effect to the ability, increasing healing taken 8% so long as the ability is slotted. Additionally, ranking up this skill will increase the damage dealt by the primary ball of energy.

Funnel Health - This morph splits the secondary ball of energy, sending it to 2 additional allies near you in addition to yourself. This allows you to passively provide a HoT to your allies as you fight in combat, sustaining the group. The healing from this ability does not stack with a nearby ally's Funnel Health, therefore a group of 3 Nightblades all casting Funnel Health will only have 1 HoT on each Nightblade.


2) Agony. This skill inflicts a disorient (Or for old-school players, a "Mez") for 30 seconds, removing him/her from the fight until the effect wears off OR the target takes damage OR the target uses a CC-break. After the disorient effect ends, a DoT is applied, dealing moderate damage for 5 seconds. This ability ignores blocks, and is best used on Sorcerer pets, with the Atronach being the grand prize. You cannot use this ability on a mounted target. Only one target can be affected by Agony at any one time.

Morphs:
Prolonged Suffering - This morph extends the the duration of the DoT, thereby dealing more damage.

Malefic Wreath - This morph changes the DoT at the end to a AoE instant damage burst, with the damage increasing by 2% for every second the enemy was disoriented by Malefic Wreath.


3) Cripple. This multipurpose skill sends a projectile towards a target, which on impact, snares the target by 40% while granting you Major Expedition, increasing your movement speed for the duration of the skill. This skill also deals a large amount of damage to the target over 8 seconds.

Morphs:
Crippling Grasp. This morph adds a small burst of magic damage on impact, as well as rooting the target for 1.5 seconds. This makes this morph ideal for chasing targets as well as kiting, as the additional root is invaluable in slowing the enemy down to create or close distance.

Debilitate. This morph refunds the cost of the skill if the target dies while affected, making this morph usable by even a stamina build for the utility the snare and movement speed bonus provides.


4) Siphoning Strikes. This skill provides a 15 second long buff to the caster, allowing Light/Heavy attacks to restore a fixed Stamina/Magicka on every hit. There is a 10% chance on hit to restore 100% more Stamina/Magicka. This skill is excellent for sustaining the Nightblade in heavy combat.

Morphs:
Leeching Strikes - This morph adds a health restoration effect to your light/heavy attacks in addition to the stamina and magicka restoration and changes the ability into a toggled ability. While the ability is toggled, you take a hit to your Weapon/Spell damage, by having them reduced by 22% while the toggle is active.

Siphoning Attacks - This morph allows the 10% bonus restoration proc to activate off all ability usage, not just light/heavy attacks.


5) Drain Power. This skill deals moderate magic damage to nearby enemies, as well as providing a Major Brutality buff to the Nightblade, increasing the Nightblade's weapon damage by 20% for 20 seconds. This skill is best used in tandem with a SnS, combining AoE damage with the tankiness to survive in the middle of a horde of enemies.

Morphs:
Power Extraction - This morph changes the skill to scale off Stamina and Weapon Damage, as well as increasing the damage per hit of the skill.

Sap Essence - This morph adds a Major Sorcery buff, increasing Spell Damage by 20%. In addition, it also adds a healing effect, which is increased by 20% for every enemy hit with this ability.


Ultimate: Soul Shred. On activation, this ultimate deals massive magic damage to all nearby enemies in a 6m radius. Enemies hit by this ultimate will be stunned for 4.5 seconds. This ultimate also provides a synergy to the lowest health ally, allowing them to perform a high damage lifedrain attack on a target that is affected by Soul Shred.

Morphs:
Soul Tether - This morph adds an additional effect, in which nearby enemies are shackled to the Nightblade by a beam that drains health every second from the victim to the caster. As a result, Soul Tether is an excellent means of turning the tables on your enemies, dealing an extremely high amount of damage while healing yourself at the same time.

Soul Siphon - This morph changes the way the ultimate works. Instead of dealing damage, the ultimate now heals all nearby allies for a massive amount every 0.5 seconds for 4 seconds. In addition, all nearby allies receive Major Vitality, increasing healing taken by 30% for 4 seconds. The radius of the ability is increased from 6m to 15m.

Master Assassin - This passive increases your weapon and spell damage by 10% stealthed or invisible. This bonus applies to all attacks. In addition, stealthed attacks will now stun for 6 seconds instead of the usual 3 seconds

Executioner - This passive accelerates your magicka regeneration by 400 for 6 seconds after killing an enemy with a skill from the Assassination Tree

Pressure Points - This passive approximately increases your critical strike rating by 2.5% for every Assassination skill slotted onto your skillbar.

Hemorrhage - This passive increases the critical damage of your critical attacks and heals by 10% so long as one Assassination skill is slotted onto your skillbar. For example, if I had an attack that hits for 1000 damage, this attack would hit for 1500 damage without the passive and 1600 damage with the passive. Additionally, when you land a critical hit or critical heal, all nearby allies will receive a Minor Savagery buff, increasing weapon critical rating by 3% for 10 seconds.

Refreshing Shadows - This passive accelerates all of your regeneration by 15% after all bonuses, which means that 1000 stamina regeneration now becomes 1150, and a set that offers 100 extra increased magicka regeneration now becomes 115.

Shadow Barrier - This passive grants Major Ward and Major Resolve on using a Shadow skill, massively increasing Armor and Spell Resistance for 4 seconds. This duration is extended by 1 second for every piece of heavy armor worn, so when wearing 7 pieces of heavy armor, the buff will last for 11 seconds.

Dark Vigor - This passive increases the Nightblade's maximum health by 3% per Shadow skill slotted.

Dark Veil - This passive extends the duration of Shadow abilities by 15%. This affects the duration of Cloak, the duration of the stun on Veiled Strike, the duration of the Path for Path of Darkness, the duration of the fear for Aspect of Terror and the duration of the fear trap for Manifestation of Terror, the duration of the shades for Summon Shade and the duration of the circle of shadows for Consuming Darkness.

Catalyst - This passive gives you 12 additional ultimate on drinking a potion.

Magicka Flood - This passive grants you 8% additional maximum magicka on having a Siphoning skill slotted.

Soul Siphoner - This passive increases your healing done by 3% for every Siphoning skill slotted, improving the heals that you initiate.

Transfer - This passive grants you an additional 2 ultimate when you deal damage with a Siphoning skill. This effect has a cooldown of 6 seconds in-between activations.

Picking your weapon and armor is important to success as a Nightblade. The first question to ask yourself is

"What kind of focus am I going for?"

There are two types of builds in ESO, one of them is a Magicka based build, while the other is a Stamina based build. By focusing on one type of build or the other, you can push your limits to their utmost potential. Sadly, since the advent of 1.6, Hybrids are no longer viable, and therefore it is best to pick a focus and stick with it.

Light armor -> Magicka
Medium armor -> Stamina
Heavy armor -> Mix this into your builds, as heavy armor offers a lot of survivability

Mandatory Weapon:
Two Handed. Two handed offers the only burst heal available to stamina users, in the form of Rally. No matter the build, you will require some form of self healing. In addition, Two Handed offers Major Brutality mixed into the heal provided by Rally. Major Brutality increases your weapon damage by 20%, and the buff carries over to your off bar, so there isn't a reason not to use a Two Handed weapon. The exception is if you have the Alliance War skill Vigor, then only you can drop the Two Handed weapon and instead rely on potions or the Dual Wield skill "Flying Blade" to provide you your Major Brutality buff.

Other weapon choices:
Dual Wield. This weapon feels like it was designed for use by Nightblades. Offering the passives Ruffian and Twin Blade and Blunt, Dual Wield is the way to go to achieve maximum damage as a Nightblade. Having two weapons in each hand has the highest spell/weapon damage in the game, due to the Dual Wield passive Dual Wield Expert. The ruffian passives allows for free 15% damage vs Off-balanced, Stunned, Rooted and Disoriented targets, something which the Nightblade class skills provide in copious amounts. Twin Blade and Blunt bestows additional bonuses to the Nightblade, depending on what type of weapon he/she is using. Swords to further amp up the damage of Nightblade skills, Daggers to increase critical chance and Maces to devastate enemy armor. Axes offer a unique synergy with the Valkyn Skoria armor set. Add in the ranged snare and high damage offered by Flying Blade to seal the deal.

Sword and Shield. Nightblades opting for more survivability in combat should consider picking up a SnS. The SnS provides a ton of bonuses to blocking, as well as access to the only reflect the Nightblade can use, namely Defensive Stance. It is highly amusing to kill a sorcerer with his own crystal fragments SnS also gives access to Power Bash, which ignores dodgeroll and can be used to take down rolling opponents. Another noteworthy ability is Low Slash, which offers a 60% snare along with a high damage spammable ability.

Bow. Nightblades who prefer to stay at a distance are pretty much forced to use this, as the ranged bonuses and skills offered by the Bow synergizes well with the Nightblade passives. Do note that the Bow is pretty much worthless in a melee fight, and therefore should not be used in Close Quarter Combat (CQC). Also note that Snipe spam, though powerful, will just get you killed by any competent player in Cyrodiil.

Mandatory Weapon:
Restoration Staff. For the same reason Stamina based Nightblades are forced to use a Two Handed weapon, Magicka based Nightblades require the usage of a Restoration Staff to heal their wounds.

Other weapon choices:
Dual Wield. Did I already mention that this weapon feels like it was designed for Nightblades? Dual Wield offers similar benefits to a Magicka build, with it being absolutely required to achieve maximum spell damage. However, you'll be pretty much just holding those weapons for show, as you will rely on your class skills to deal damage instead of mixing weapon and class skills together. A pair of twinned swords or a sword and an axe are pretty much your only choices, as none of the other types of weapons offer any benefit to a Magicka based Nightblade.

Sword and Shield. SnS still offers it's great defensive benefits to blocking. Pair this with Sap Essence to create what is known as a "Sap Tank".

Destruction Stave. Destruction Staves offer the Magicka-based Nightblade some utility in the form of Destructive Touch as well as a reliable ranged damage skill in the form of Force Shock. However, Weakness to Elements is outclassed by Mark Target, and Impulse is outclassed by Sap Essence.

Vampire -> Dark Stalker - This passive removes the movement speed penalty of sneaking, which is invaluable to Nightblades, who are a class based around stealth gameplay.

Fighter's Guild -> Dawnbreaker -> Flawless Dawnbreaker (Morph) - Flawless Dawnbreaker offers a passive 8% increase to your weapon damage, which is invaluable to Stamina Based Nightblades. Dawnbreaker is a melee ranged ultimate that ignores dodgeroll, making it very useful versus rolling enemies.

Mage's Guild -> Entropy - Entropy and its morphs provide a Major Sorcery buff to the caster, making this skill essential on Magicka Focused Nightblade builds.

Alliance War -> Assault -> Vigor - Vigor is the only other stamina based heal, which means that it is essential to Stamina Based Nightblades if they do not wish to use a Two Handed Weapon.

Alliance War -> Assault -> Magicka Detonation -> Proximity Detonation (Morph) - An interesting combination with Shadowy DIsguise, this allows a Nightblade to activate this from out of combat, then cloak into the middle of an enemy group. Shadowy Disguise will then ensure the explosion is a critical hit. A certain AD nightblade I know has managed to crit 22k with this explosion.

Teleport Strike -> Veiled Strike - The standard Nightblade one-two combo.

Snipe -> Ambush - A high damage opener from stealth.

Healing Ward -> Cloak - Enemies can't hit what they can't see, this ensures you get the most out of your healing wards.

Magicka Detonation -> Teleport Strike -> Sap Essence -> Shadowy Disguise - A hidden explosion from stealth.

Siphoning Attacks + Merciless Resolve + Shieldbreaker (IC Tel-Var Armor set) -> Entropy -> Assassin's Will - Buff up, restore your resources, devastate enemy shields and end the combo with a massive damage ranged attack.

1) Hunding's Rage - This crafted set bonus provides a massive boost to damage with it's excellent bonuses. A staple in (almost) every stamina-based damage build.

2) Shieldbreaker - This Tel-Var stone armor set provides good bonuses, along with the ability to destroy shielded targets with simple light attacks. An excellent means to take down Sorcerers.

3) Skirmisher's Bite - This set provides a good mix of damage and regeneration, as well as a huge boost to damage on activating a dodge roll.

4) Way of the Air - Similar to Skirmisher's Bite, this set offers even more regeneration as well as stealth detection at the cost of some damage.

5) Morag Tong - Morag Tong offers 2 weapon damage set boni, allowing a huge increase to damage dealt.

6) Shadow Walker - Shadow Walker provides unique synergy to the innate cloaking ability of the Nightblade, allowing the Nightblade to turn cloak into a mimicry of the Sorcerer's Dark Deal.

7) Powerful Assault - If you are constantly activating alliance war abilities (Rapid Maneuvers, Caltrops, Vigor), this Tel-Var stone armor set bonus provides a bonus to damage similar to Hunding's Rage, but with one difference. The bonus this set provides hits nearby allies as well as yourself, giving a bonus to both spell and weapon damage. Excellent for use in groups.

8) Ravager - This armor set allows you to have a 10% chance of gaining a massive amount of weapon damage on a melee attack, allowing for some impressive bursts, should this set activate.

1) Martial Knowledge - This set provides a huge bonus to spell damage, making this a staple of Magicka-focused Nightblades who seek to deal damage

2) Healer's Habit - Magicka-based Nightblades sport a panoply of HoTs, which allows the 5pc bonus of Healer's to shine. Even if you do not use the set for it's 5pc bonus, the 2-4pc bonuses are highly competitive, earning it a spot on most builds.

3) Phoenix - This Tel-Var stone armor set literally gives you a second chance in a fight, and when your health reaches zero, instead of dying, you turn into a statue. After 4 seconds, you explode in a burst of flame and are healed for a significant portion of your health. Also offers excellent 2-4pc bonuses.

4) Reactive Armor - This Tel-Var stone armor set reduces the damage you take 35% when CC-ed. This allows you to survive through CC-combos that would otherwise kill you, allowing you to conserve some stamina instead of having to break free every time you get CC-ed.

5) Scathing Mage - The Magicka version of Ravager, this armor set provides a 10% chance to gain a massive boost to spell damage when you inflict a critical hit. As Nightblades come with innately high crit %, this item set is excellent on a Magicka-Based Nightblade.

6) Spell Power Cure - This armor set allows the user to provide a damage boost to an ally, should the user heal them when they are at full health. As Nightblade abilities come with a ton of HoTs, this allows the bonus provided by this armor set to be pretty much constantly active.

7) Seducer - This crafted armor set offers 8% cost reduction on all Magicka-Based abilities as well as providing high amounts of Magicka regeneration. A staple for sustain-based Magicka Nightblades.

8) Armor Master - An interesting way to offset the natural squishyness of Light Armor, the crafted armor set Armor Master offers a 5.2k increase to Armor and Spell Resistance on activation of an armor ability (Annulment, Evasion and Immovable) that stacks with Major Ward and Resolve. Use of Armor Master can render Light Armor to be just as tanky as Heavy Armor.