Gear Review
The Engine Guardian monster set is quite a strong sustain option especially on builds including this one that tends to have a high skills-per-minute rotation or usage. You can play to your sustain options depending on which the Engine Guardian grants you. If Health, you could probably afford to drop Block and get some Stamina back or Magicka back if you want to stop casting things. If Magicka, you can spam more Magicka abilities, if Stamina, more Stamina abilities or do other things such as Sprint.
Drake's Rush is a solid primary set to use to gain a significant amount of Ultimate through Major Heroism which will stack with Minor Heroism from your Heroic Slash and the Ultimate generation you get from blocking damage or light attacking. It's a strong group utility set in terms of indirectly adding more damage by giving more Ultimate to the rest of the group.
Torc of Tonal Constancy is a great Mythic to use for sustain purposes. If you're less than 50% on Magicka, you get a significant amount of Stamina recovery and if you're less than 50% on Stamina, you get a boost to your Magicka recovery. This in addition to the Engine Guardian will mesh well with most tanking playstyles.
Due to the nature of the gear setup here, you will be able to have one ring or armor piece of Trainee which will grant you an additional Max Health.
Blessing of the Potentate will be another three-piece item set that you will use in full function on the backbar. The 15% Ultimate cost reduction in addition to the Templar ult cost reduction passive can stack leading to only 205 Ultimate being needed for a Solar Prison or Aggressive Horn.
Your two piece set on the frontbar will be the Master's One Hander and Shield which gives back a large amount of healing upon applying Taunt which lets you bypass the need to cast a different healing skill as you're taunting different things or bosses in most of the 4 man content in ESO.
Skills Review
The skills are quite self-explanatory:
Echoing Vigor is a nice 10 second Heal over Time ability to keep up on both yourself and the group whenever possible.
Pierce Armor is your primary melee taunt that inflicts Major and Minor Breach on targets.
Radiant Ward is your go-to Magicka spammable skill that will let you shield against incoming damage covering your Healthbar.
Heroic Slash is a skill that provides Minor Heroism as a buff and Minor Maim as a target debuff.
Living Dark is one of the few ways Templar tanks have to snare targets that are attacking them but it also provides a nice base heal every time you get damaged.
Remembrance is the frontbar Ultimate to use for its Major Protection and crowd-control immunity on yourself while providing a huge amount of healing for those around you.
Restoring Focus is a must skill to have as it not only gives you Stamina sustain for Blocking, Roll Dodging or Breaking Free (even if you're not standing in the rune) but also a heal-over-time (which you must stand in the rune for) that scales off of your Max Health rather than your Max Magicka/Stamina or Weapon/Spell Damage.
Inner Rage is your ranged taunt option that can be useful for fights where something spawns far away and could hit your group from a distance or at a melee range once they approach them away from your position.
Blockade of Frost is a good way to keep up the Crusher enchantment on a target in front of you while providing frost shields that absorb projectiles for you and your group while also giving you Magicka sustain through the expiration of the shields.
Extended Ritual is a passive Heal over Time to keep up which also provides the Purify synergy to the ret of the group, it also serves as a potential Purge from DoT effects on yourself.
Silver Leash is a skill you may need to Pull in enemies that may be going after one of your group members or simply an ranged enemy that's just standing at a distance so that you can stack them together for your group to burn down in one spot with their DoT placements.
Aggressive Horn is a good Ultimate to use to give 10% additional Magicka and Stamina (indirectly damage) and Major Force (more Critical Damage) to your group members. Solar Prison or Barrier is good to use as alternatives on the backbar.
Craft
Warfare
Fitness
Champion Points Review
The Warfare Slottables are quite typical for maximum mitigation as a tank with Ironclad, Unassailable, Duelist's Rebuff and Enduring Resolve.
The Fitness Slottables include Boundless Vitality (Max Health), Fortified (more Armor), Rejuvenation (more recovery but not Sustained by Suffering slottable as you can cleanse DoTs or status effects with Extended Ritual) and of course Shield Master (reduces the cost of your Radiant Ward casts).
Introduction (Update 32, Deadlands)
This build is NOT recommended to take to Veteran Trials.
The Hero Templar tank is intended to be fully self-sustaining while providing safety nets in the form of Healing over Time and taking control of the fights whether it's trash mobs or boss fights without significant sustain hits for the group in all tiers of 4 man content including the veteran Dragonstar and Blackrose Prison arenas.
For a beginner's guide to tanking in The Elder Scrolls Online, you can refer to this guide.
Recommended Races for this build are Imperial, Nord and Argonian. For race recommendations you can refer to this video. Note that the Attribute allocation may differ depending on your race. For the purpose of the build showcase, we used Imperial.
Recommended potion for this build is an Essence of Health (tri-stat).
Recommended food for this build is Bewitched Sugar Skulls.
Recommended Mundus Stone is The Serpent.
For gameplay and the video showcasing this build, refer to the video.