This isn’t my best work as it was my first, if you want to see a much better concept that was more thought out and works much better with the game plus being more unique you can find it here - https://forums.elderscrollsonline.com/en/discussion/540799/new-class-concept-aquamancer#latest

I love the classes in Elders Scrolls Online, and am very happy when I hear that they will be adding a new one in the next DLC, for example, Morrowind and Elsewyr. That's why I decided to post a concept for a class idea I've had in mind that I personally feel would be very enjoyable to play whilst still not being overpowered and working with the game mechanics. I haven't gone into huge detail about all the abilities in terms of numbers and buffs/debuffs but if you wanted them I'd be more than happy to share, just ask.

Skill Line 1 - Julianos' Shield (This skill line mainly focuses on barrier magic which I would find really interesting and useful in the game either adding another branch to the support section or being utilised by tanks but possibly damage also for quick protection. This skill line allows for barriers to be used to block damage for example a damage shield on your team but also to channel a large shield in front of you blocking all damage, for example, but more below.

Ultimate - Shield of the Divines: Invoke the power of Julianos and channel a 360-degree barrier that stays up as long as you have Magicka or until it breaks. The barrier will surround the caster and anyone who is inside it from damage. Players can shoot out of it but any damage directed to a player inside the shield will be absorbed.
Ultimate Morph 1 - Julianos' Wisdom: Using the mouse buttons or controller left and right triggers, you can direct the flow of magic of the barrier. By holding right-click or right trigger, you direct the force of Magicka towards the right side blocking more damage on the right making the shield durability decrease less if damaged from the right side, if the left click or left trigger is held, you direct the force of Magicka towards the left side blocking more damage on the left making the shield durability decrease less if damaged from the left side. Now this won't mean the opposite side of the barrier is completely undefended, it will be weaker due to less Magicka being channeled into it and so it will increase the damage done to the barrier if hit on the side that isn't being focused. You don't have to direct Magicka to one side, it can be spread evenly like before it's morph. It will also drain your Magicka faster as you will be increasing the defense of that side of the shield. The left and right sides would be determined by the position of the player whilst casting as the player will not be able to move or do damage during this ultimate as they are channeling the shield so it will be up to the rest of the team to do damage for them whilst being protected. This is why I suggested it be more support focused as if the team isn't taking damage due to the shield then they won't need to be healed.
Ultimate Morph 2 - Blessing of Magnus: Your shield will have increase durability and decreased Magicka consumption as well as your team gaining minor resource regeneration based on the lowest one whilst standing in the barrier. This is particularly useful for a support or tank player.

Ability 1 - Untouchable: Gain a personal damage shield that lasts until it's destroyed or your Magicka runs out. You can move and deal damage during this. (toggleable)
Ability 1 Morph 1 - Extended Protection - Your shield will now drain Magicka slower and have higher durability. Once destroyed or Magicka has run out, it will release a small shockwave of the percentage of damage that you absorbed.
Ability 1 Morph 2 - Aetherian Protection: When casting the ability your shield splits and will attach itself to you and a maximum of 3 other players in a certain range.

Ability 2 - Divine Punishment: Trap an enemy in a divine bubble which immobilises them for a few seconds or until they break out of it.
Ability 2 Morph 1 - Divine Sacrifice: Spend a portion of your physical energy (stamina) to slowly crush the enemy trapped inside the bubble dealing damage as long as they are trapped.
Ability 2 Morph 2 - Divine Mercy: Cast the bubble on an enemy that lasts only one second freeing them shortly after capture. They will now have Magicka drain for the next few seconds as well as being immobilised for that initial one second.

Ability 3 - Reflection: Cast a reflective shield on an enemy causing whatever damage they do to be sent back at them for as long as the ability lasts (a few seconds) or they are cleansed of it.
Ability 3 Morph 1: Horrific Reflection: Cast the reflective shield on an enemy but instead of reflecting their damage, very small portions of their team's damage (PvE it's just an enemies damage but for PvP, it would be their alliance team players) are cast onto them taking some of it away from who it was initially directed to and sent to the enemy with the shield. (Stamina)
Ability 3 Morph 2 - False Reflection: Cast the shield on an enemy to cause them to run in fear from what they have seen lasting a few seconds or until they break free causing any damage they take whilst the shield is active to be increased.

Ability 4 - Divine Exchange - Cast a barrier on your self that will change any damage into your lowest resource, health, Magicka, or stamina. Active for a few seconds.
Ability 4 Morph 1 - Divine Endurance - Casting the barrier and absorbing damage will not restore health but will restore more Magicka and stamina whilst active,
Ability 4 Morph 2 - Divine Interception - Casting the barrier will cause a percentage of damage absorbed to heal you for a few seconds, the barrier will last longer.

Ability 5 - Unstable Barrier - Fill a barrier full of Magicka and sent it at the enemy exploding on impact dealing magic damage.
Ability 5 Morph 1 - Collapsing Barrier - On impact, the barrier will also absorb Magicka and increases in speed.
Ability 5 Morph 2 - Stable Barrier - The barrier will no longer do damage but will heal the ally it is directed for and will apply a shield lasting a few seconds or until destroyed.

Skill Line 2 - Blessings of the Divines (This skill line is mostly focused on healing and buffs, it is mainly useful for support players but tanks and damage players can use it for buffs and resource regeneration if needed.)

Ultimate - Sacred Ground: Bless the ground with the power of divines creating a large area AOE that heals all allies that stand within it and cleanse them of their debuffs.
Ultimate Morph 1 Sacred Air - The debuffs that are cleansed are put onto the nearest enemy to the ally who is cleansed.
Ultimate Morph 2 Sacred Water - The effect now follows the caster and cleanses and heals the allies around the caster.

Ability 1 Breath of the Divines - Exhale the sacred breath of the divines on your allies increasing their damage and defense for the duration (a few seconds).
Ability 1 Morph 1 - Exhale of the Divines - Increases range and amount of defense and damage bonus.
Ability 1 Morph 2 - Inhale of the Divines - Take in the debuffs of your allies and release them out as ranged healing.

Ability 2 - Arkay's Favour - Invoke the rites of Arkay controlling life and death with the left click/trigger you decrease your enemy's damage and defense, with the right-click/trigger you give buffs to you allies regenerating their resources.
Ability 2 Morph 1 - Arkay's Wrath - Channel the wrath of Arkay by debuffing the enemy and instead of buffing your allies with right-click/trigger, you attach to the enemy leeching health from them while tethered.
Ability 2 Morph 2 - Arkay's Benevolence - Increases the strength of buffs and more resource regeneration.

Ability 3 - Kynareth's Boon - Invoke the power of Kynareth's wind gaining a speed boost and decreasing any ability cooldowns by one second.
Ability 3 Morph 1 - Kynareth's Winds - Share the power of Kynareth will your allies giving them speed boosts and quicker ability cooldowns.
Ability 3 Morph 2 - Kynareth's Champion - Gain the power to fly through the air launching yourself forward damaging any enemy and healing any ally you dash through.

Ability 4 - Mara's Love - Bless your allies with a damage shield that heals the wearer for a percentage of the damage stopped by the shield.
Ability 4 Morph 1 - Mara's Guidance - Also gives this shield to yourself and strengthens the shield on only you.
Ability 4 Morph 2 - Mara's Gift - Strengths the shields given to your allies providing a longer defense and duration.

Ability 5 - Divine Resurrection - Gain the approval of the divines and for the next few seconds the time it takes for you to resurrect someone is decreased.
Ability 5 Morph 1 - Divine Life - Also regenerates all resources of you and the resurrected player.
Ability 5 Morph 2 - Divine Beginning - Exchange your life for another dying to instantly resurrect another.