With this boss you can't really heal with regular heals or HoT due to its decay debuff, you can if you time it but you risk killing your party. You can use Auras UI and monitor the decay debuff, but the window to heal is absolutely tiny. It is recommended to use health vamp here but if your class does a "lifesteal-esque" heal you will not need health vamp.

This boss as a ledgermayne like mechanic where there are two platforms, bottom left and right, and you are required to move to them immediately when they light up or face a nuke. Everytime dage kills a player he heals 500k HP, reset after 3 deaths.

Class Enhancements Consumables Extra Information
CaV Health Vamp or Dauntless/Anima/Vainglory Fate/Destruction Elixir + Scroll of Enrage Loop taunt Dage with 3 and enrage. Don't hit your 4 skill as it is a HoT unless Dauntless.
VDK Valiance or Dauntless/Anima/Vainglory Fate/Destruction Elixir + Potent honor Use your 5 skill to decay when he says "I possess the power of the legion at my disposal" to prevent him from healing.
LOO Health Vamp/Forge/Vainglory Body + Potent Honor Focus on dage, keep buffs up but do not use your heal.
AP Health Vamp/Forge/Vainglory Fate/Destruction Elixir + Potent honor Focus on dage, debuff him and stack broken seals. Do not use your heal.

Alternative Comps

Probably the safest way to do this run.

Class Enhancements Consumables Extra Information
CaV Health Vamp or Dauntless/Anima/Vainglory Fate/Destruction Elixir + Scroll of Enrage Loop taunt Dage with 3 and enrage. Don't hit your 4 skill as it is a HoT unless Dauntless.
LDK Valiance or Dauntless/Anima/Vainglory Fate/Destruction Elixir + Potent honor Loop your 5 skill as it has decay.
LOO Health Vamp/Forge/Vainglory Body + Potent Honor Focus on dage, keep buffs up but do not use your heal.
AP Health Vamp/Forge/Vainglory Fate/Destruction Elixir + Potent honor Focus on dage, debuff him and stack broken seals. Do not use your heal.
Class Enhancements Consumables Extra Information
CaV Dauntless/Anima/Vainglory Fate/Destruction Elixir + Scroll of Enrage Loop taunt Dage with 3 and enrage. Don't hit your 4 skill as it is a HoT unless Dauntless.
VDK Dauntless/Anima/Vainglory Fate/Destruction Elixir + Potent honor Use your 5 skill to decay when he says "I possess the power of the legion at my disposal" to prevent him from healing.
LOO Health Vamp/Forge/Vainglory Body + Potent Honor Focus on dage, keep buffs up but do not use your heal.
LR Dauntless/Wiz/Vainglory Sage/Malevolence Elixir + Potent Honor Focus on dage, keep buffs up.