Organized 12 man content Tank 1/2 (main) - Arcanist Построй PvE - ESO

Elemental and wall of elements provide major and minor breach ≈ -9000 armor

Runic sunder and crusher enchant on ice staff ≈ -4400 armor

Debuffing enemies for 13400 armor in total, leaving 4800 armor 

Frostguard and Runeguard of freedom gives group a long major/minor resolve and minor evasion buff, increasing group armor by 9000 (15%dmg reduction), and reducing aoe dmg taken by 10%.

Minor maim is applied with runic sunder, decreasing enemy hits by 5%

Minor vulnerability and minor brittle is applied with elemental susceptibility. Providing 50% up time on minor vulnerability and maybe 33%uptime on minor brittle

Major cowardice. And major/minor maim is applied with soul blast, shield throw and runic sunder. Decreasing enemy dmg done by 25% total

Major vulnerability (+10% enemy dmg taken) can potentially get 100% up time if timed correctly from archdruid devyric and turning tide.

Pearlescant ward provides 230 weapon power to group

Storm attronach provides major berserk +10% dmg dealt

All in all dds theoretically do ca 45% more dmg due to your buffs and enemy debuffs, and enemies only do 66% of their normal damage to your group members.

Skill priority goes like this:

Boss fight:
Before engagement
1. Runeguard of freedom
2. Frostcloak

In fight
1. Runic sunder
2. Elemental susceptibility 
3. Elemental Blockade
4. Soul blast

5. Shield throw

6. Heavy attack

7. Greater storm attronach