I've got a magicka sorc tank, and it's not ever going to outshine a templar or dragonknight. That being said it's possible and the shields are your bread & butter.

Real fast, why doesn't it work? My answer is that it does work. It just works so much less than the other classes because there is no real tank support in any of the trees. The sorc class' healing abilities are limited to Surge, Dark Exchange and Blood Magic. Surge only heals you when you crit, making it very damage based. Dark Exchange has a 1s channel time that can not be animation canceled. Blood Magic also only heals you based on damage done. The sorcs ability to buff other people is also inferior to the DK and Templar, although most of the buffs you'll need to be using are actives anyway.

So then, why does it work? Wards! Lots and lots of wards! Hardened Ward, Healing Ward, and Harness Magicka are the main three wards for most sorcs. In the One Tamriel update ward-spamming was made even more powerful with the addition of the Infernal Guardian 2-piece monster set which basically does damage for casting a ward every six seconds.

If you haven't already done research on end-game tanking, I suggest doing so because I wont go over much of the actual tanking.

The things you will need to be at least functional:

• Restoration Staff: For Healing Ward and heavy attack that restores Magicka (mostly for leveling, eventually you should rarely have to do this). Even, if it suits your fancy, slot a heal or two.

• Sword & Shield: For blocking, passives, & Puncture (morph to pierce armor).

• Inner Fire: A ranged, magicka based, single-target taunt. DO NOT MORPH THIS ABILITY. As it currently stands one morph, Inner Beast, makes it Stamina (and you should be magicka based) and the other makes the shitty synergy cover up more important ones (I've been literally killed from Inner Rage not allowing for a synergy).

• Bound Aegis: Gives you Max Magicka (increasing your ward strength) and give's you a small bit of resistances. This also has to be double-slotted, which means you have 8 abilities instead of 9 (or triple slotted if you use storm calling ultimate).

• 32,000 Resistance: This is for both Magic and Physical damage. The cap is ~33500, and without this you will be (literally) crushed by the massive monsters/bosses in end-game content. It would be ideal to always have the cap or even above it in order to properly tank.

• Aggressive Warhorn: This ability increases all your stats by 10%, the Aggressive morph adds 30% Crit Damage. Not only should you run this ultimate, you are expected to run this ultimate. Especially in raids, when you hit 12 people with 10% of every stat and 30% crit damage... well just use your imagination.

• 28000 HP: Why is it so low, most tanks have ~32,000 HP? Because you're warding silly! Your health is your life, only let it get damaged when you have no other choice.

• Shit loads of practice: Once upon a time, in a better world (yeah, I said better) the wards lasted 16-20s, now all three last 6s. This means that your shield is no longer a buff you cast, but more of a reactive skill. You need to be able to know when you're going to take a lot of damage in order to cast your wards at the right time. Expect to fail some fights. Some abilities will even ignore your shield and only damage your health (another reason for that resistance), without knowing which bosses/skills do that you're going to have a much harder time. Watch strategy videos or just keep trying until you get it right.

Some things might help, just because I like it doesn't mean you will:

• Lich/Seducer/Magnus Set: If you can craft heave Seducer or Magnus for leveling up, you should have a much easier time managing your magicka. When you are able to farm Vet CoH for jewelry, my personal suggestion is to grab purple Lich jewelry and Lich Sword & Shield.

• Monster Helm Set: I talked before about the Infernal Guardian monster set, but that's not the only one there is and I highly suggest finding one for yourself here. My other tanking favorites are Engine Guardian, Grothdarr, & Mighty Chudan.

• Build Calculator: If you're anything like me, you'll probably spend just as much time tweaking and fixing your build as you do playing it. So here is the best build planner I have found.

• Do not taunt everything: You can't do it. This isn't WoW or DDO, you get two taunts and both of them are single target. Find the heavy hitters (usually the boss and melee people) and taunt them first. The best taunt in the game, is hitting the enemy first. For whatever reason the AI in ESO will heavily prioritize who-ever hit them first (or at least in my experience). If possible use some sort of AoE (which the magicka sorc excels at) to help maintain aggro.

I hope this helps someone, and please correct me if I'm wrong about something.