Here's the build I personally use, put it together myself.

Gear

I run 7 Light Armor. I see no reason to wear heavy at all. At vet 12, wearing full legendary gear (3 set alessia's bulwark, 3 set Toruggs Pact, 3 set Seducer), and a 600 armor ring, I sit at just under 2000 armor and 2100 spell resist. Along with that, I have a massive magicka pool for all my class skills. Heavy is really lacking imo.

As for traits, I put Reinforced on high armor pieces (head, legs, chest), Impenetrable on shield and one other piece, and divines on the rest. I have the Defending trait on my sword and healing/destro staff. I use the Magicka return enchant on weapon.

Attributes and Stats
0/49/0 for attributes. You get the most out of putting all your points into health and enchanting for other things.

For Enchants, I usually go Health on shield and full Magicka on everything else, but it can be beneficial to put some into stamina for certain fights, such as the third boss in Vet Wayrest sewers where you are required to burn stamina to break out of fear. For nearly every other fight, 1200 stamina is sufficient to keep up Immovable and block heavy attacks.

The Mundus I use most often is The Mage, although if you feel yourself lacking in stamina, you could use The Tower, or if you want more health, The Lord.


Skill Points

Aedric Spear Line:
Empowering Sweep (Radial Sweep Morph)
Biting Jabs (Puncturing Strikes Morph)
Binding Javelin (Piercing Javelin Morph)
Blazing Spear (Spear Shards Morph)
Piercing Spear (optional 2/2)
Spear Wall (2/2)
Burning Light (optional 2/2)
Balanced Warrior (2/2)

Dawn's Wrath Line:
Solar Disturbance (Nova Morph)
Vampire's Bane (Sun Fire Morph)(optional)
Dark Flare (Solar Flare Morph)(optional)
Power of the Light (Backlash Morph)(optional)
Blinding Flashes (Blinding Light Morph)
Enduring Rays (optional 2/2)
Prism (optional 2/2)
Illuminate (2/2)
Restoring Spirit (2/2)

Restoring Light Line:
Remembrance (Rite of Passage Morph)
Breath of Life (Rushed Ceremony Morph)
Radiant Aura (Restoring Aura Morph)
Extended Ritual (Purifying Ritual Morph)
Channeled Focus (Rune Focus Morph)
Mending (optional 2/2)
Focused Healing (optional 2/2)
Light Weaver (optional 2/2)
Master Ritualist (optional 2/2)

One Hand and Shield Line:
All Passives

Destruction Staff Line (optional):
Elemental Blockade (Elemental Wall Morph)
Elemental Ring or Pulsar (Impulse Morph)
All Passives

Restoration Staff Line:
Healing Springs (Grand Healing Morph)
Rapid Regeneration (Regeneration Morph)
Combat Prayer (Blessing of Protection Morph)
Spirit Siphon (Force Siphon Morph)
All Passives

Light Armor Line
All Passives

Heavy Armor Line
Immovable or Unstoppable

Vampire Line (unnecessary but recommended. If you are a Vampire you need a fire resist ring.):
Devouring Swarm (Bat Swarm Morph)
Supernatural Recovery (2/2)
Undeath (2/2, currently broken sadly)
Unnatural Resistance

Fighter's Guild (optional but recommended):
Ring of Preservation (Circle of Protection Morph)
All Passives

Mage's Guild (optional but ALMOST necessary):
Volanic Rune (Fire Rune Morph)
All Passives

Undaunted Line (REQUIRED):
Inner Beast (Inner Fire morph)
Bone Surge (Bone Shield Morph)

All Racial Skills


Bars and Combat

The beauty of the Templar Tank is that it can fill two of the three roles as needed. A good templar tank can tank AND heal a dungeon with three DPS. A good templar tank can also tank while putting out some great damage. Flexibility is great with this class.

1: One Hand and Shield:

1. Inner Beast. This is your taunt. It is magicka based, which frees up your stamina for blocking and immovable. Use it every 10 seconds or so to keep aggro on your current target/boss.

2. Biting Jabs. This is your main damage skill. Use it when you don't need to use your magicka on Bone Surge or on trash.

3a. Volcanic Rune. This is one of your most important spells. It is the best CC in game, and it can turn difficult trash into pathetically easy trash.

3b. Blinding Flashes. Use this on trash if you have a DPS or Healer who spams Volcanic Rune regularly.

4. Immovable/Unstoppable. This is your best defensive spell and it is the only thing you will use Stamina for besides blocking. Stagger this with other defensive spells, or stack it for heavy damage phases.

5.Bone Surge. This is a great armor buff which makes heavy armor nearly useless. With a large magicka pool, you can maintain this buff as long as you need to, and it has a great synergy for your party, too.

6. Empowering Sweep: Decent damage, decent armor buff, cheap.



Now, here's where the Templar's flexibility comes into play. I have three different setups I use for my third bar depending on the group's needs.

2a. Healing Staff (Healing/Support)

1a. Radiant Aura: This is mostly for use when you need to recover some stamina. It's great for when you're running low stamina builds.

1b. Spirit Siphon: The utility in this spell is just immense. You heal the group while increasing magicka return for them and yourself.

2. Rapid Regeneration: Decent HoT that you can spam on yourself and others before and during fights.

3a. Healing Springs: Use this spell when your group is stacked for some great healing. You can cast 3-4 of these at once for burst healing.

3b. Combat Prayer This underrated spell gives you and anyone standing in front of you a great armor and spell resistance buff, a nice big heal and a damage buff. What's not to like?

4. Channeled Focus This is an amazing spell when you can stand still, which is surprisingly often in this game. If you have immovable, bone surge and combat prayer up, cast this and you're basically invincible. You also get some nice magicka regen out of it.

5. Breath of Life: This is your most reliable group heal. Though expensive, it can save lives and turn the tide of battle when your healer runs out of magicka or you're out of range. (Assuming you have a healer, that is )

6. Remembrance: Nothing like a big free AoE heal to save the day with.


2b. Healing Staff (Single target DPS)

1. Vampire's Bane: This is a great damage spell that does decent damage up front and leaves a nice big DoT on the target,

2. Power of the Light: This is the highest damage spell in the game when used correctly. If your group is putting out enough damage, it will hit for 1600ish every time. Use this as much as possible.

3. Dark Flare: Use this before Vampire's Bane and spam it otherwise. This is your main DPS spell.

4. Channeled Focus: Same great benefits as described above.

5. Breath of Life: It's always good to have at least one heal.

6. Solar Disturbance: This is a very nice AoE ultimate which also reduces damage done by enemies and snares them. It's an all-in-one utility spell. It also has a nice synergy!


2c. Destruction Staff (AoE DPS)

1. Elemental Blockade: This spell was chosen over Unstable Wall because it does comparable damage and you have more of a chance of keeping your enemies within its bigger radius.

2. Pulsar/Elemental Ring: This is your AoE spam spell. It does a lot of damage.

3. Volcanic Rune: You can never have too much Volcanic Rune. If you're going to be tanking in a dress with a staff, you'd best keep control of your enemies.

4. Channeled Focus: This is a mainstay in all three loadouts for a reason.

5. Breath of Life: Same as above.

6. Devouring Swarm: This spell is INSANELY good. It is THE best ultimate for AoE tanking because it works as both an emergency heal and an amazing AoE damage spell. There are a lot of things in this game I could not do without this spell.





So there you have it... I hope this immense wall of text helps you in some way. As an experienced Templar player my goal is to educate others while we wait for stamina buffs!

Heavy tanks can take a hit, but they're not going to excel at doing a whole lot else. The purpose of wearing Light Armor is to have the spell cost reduction, regen, and superior spell resistance to do things BESIDES taunt and block. Light armor's only downfall is lack of armor, which can be completely offset by an armor ring or two. It doesn't make any sense to not AT LEAST wear two pieces.