[Sevagoth's Shadow]

Gameplay
Sevagoths Exalted Form, this is the melee murder machine. Using S1 to group enemies, S2 is great movement as well as health sustain. S3 for causing additional damage. This one's not complicated, just claw things for big numbers.

Build here is to maximize the Harvest debuff mostly and get solid LifeSteal. Flow is used in place of Efficiency to the same effect without the Duration downside.

Aura - 100% preference, some options are Steel Charge, or even Swift Momentum. The always great Corrosive Projection is an easy fallback as well.

Arcanes - 100% preference, some options are Energize, Grace, [Guardian], and Strike or [Fury].

Umbral
If you're willing to shell one out drop [Stretch] for [Umbral Fiber] and complete the set or just to reduce the total Forma cost.

Ability Breakdown

1. Embrace
   Tether and pull in enemies in a frontal cone.
   Enemies are "Lifted" towards you.
   Strength - N/A
   Range - Range but not Radius
   Duration - Lift duration

2. Consume
   Dash forward dealing damage and healing yourself.
   Inflicts Radiation damage and Knockdown.
   Can be targeted.
   Strength - Damage and LifeSteal%
   Range - Distance traveled
   Duration - N/A

3. Death's Harvest
   Debuff enemies in a radius around you to take additional damage from all sources.
   Enemies marked fill 5% Death Well.
   Strength -Vulnerability %
   Range - Radius
   Duration - Debuff Duration

4. Exalted Shadow
   Usable once Death Well > 75%
   Drains 1% of Death Well /Second
   Can be reactivated to resume control of Sevagoth.
   Sevagoth will heal 1% Health/1% Death Well consumed upon Reunite.
   Strength - N/A
   Range - N/A
   Duration - N/A