Pure farm nekros for dedicated farming squads (e.g. Steel essence, resources, arena endo)
Helminth
Endo Arena
[Nekros] can take the role of [Nidus] by subsuming Larva and droping [Primed Continuity] (for [Speed Drift] or [Vitality] if you can fit) in order to reduce Larva duration to make it more spammable.
If you want more health, replace rolling guard, fleeting expertise or augur reach with vitality.
Adaptation/[Health Conversion] are optional (but you should try to stay out of enemy fire completely).