How Nourish (2) works.
Casting Nourish (2) on different units gives you different buffs, they are as followed;
Heavy, flying or summoned units: Strike buff (Adds toxin damage to all attacks for nearby friendlies)
Melee units: Armor Buff (Deal toxin damage around friendlies whenever they take damage)
Ranged units: Energy Buff (Multiplies the energy gained for all nearby friendlies)
The buff Nourish (2) you obtain is determined by which enemy was consumed first by feast, if multiple enemies were consumed by feast you can cycle through buffs by holding Nourish (2) down.
If you wish to have an additional 10% strength feel free to install a maxed [Transient Fortitude] (rank 10). I chose a Rank 8 to have the buff as close to 1 minute duration possible.
You can easily hold 3 enemies with feast to benefit from 150+ armor without suffering too much from energy loss.
Guide might be updated later today with a video explaining how I play [Grendel].
For now, have fun and feel free to ask any questions in the comments!