Vectis is a cyclic two phase fight that has one main mechanic that is applied at the start of the fight called Omega Vector. Omega vector is a debuff that deals shadow damage over time and upon expiration will jump to the closest ally, that, when it jumps, leaves a stack of Lingering Infection, which increases nature damage taken by 5% per stack.
Phase 1 of the fight happens when Vectis is attackable. During this time he casts Contagion which deals nature damage to all players. Due to the nature of Omega Vector and Lingering Infection, the impact of this ability increases over the course of the fight. Vectis will also cast Gestate on a random player dealing shadow damage to them as well as any players nearby and stuns the primary target for 5 seconds. After the stun wears off, a Plague Amalgam will spawn, which only cast one ability, Immunosuppression. Immunosuppression debuffs every raid member with a significant healing absorb that stacks if it isn’t removed before the next cast. Dealing with Immunosuppression is important to avoid a raid member having a large healing absorb when they are in danger of dying, use large healing cooldowns when Immunosuppression lines up with Contagion.
In Phase 2, Vectis becomes untargetable and becomes a pool of blood. Any players who come in contact with the pool of blood will gain a stack of Lingering Infection. During this time, Vectis will cast Blood Geyser which are beams of blood that shoot out from the blood pool and deal shadow damage upon impact with any players. These Blood Geysers also apply stacks of Lingering Infection. The other mechanic in this phase is Plague Bomb which causes multiple circles to spawn around the room. These circles must be soaked by one person and just one person. If any circle goes unsoaked, a Plague Amalgam will spawn which adds to the number of Immunosuppression casts. You only want one player to soak each of these Plague bombs as the damage does not split. The goal of this phase is to avoid getting hit by Blood Geysers while effectively soaking Plague Bombs as a raid.
- Use Downpour on stacks of players after Immuno and Contagion casts.
- Keep Healing Rain on stacks of players when they are afflicted by Immuno.
- Consider saving charges of HST for Immuno casts.
- Rotate healing cooldowns liberally when you have Immuno debuffs out on the raid and the boss is casting Contagion.