Grendel Umbra. 23.75 second duration on Nourish, use as needed.
Aim-glide and Feast, un-Feast puke, swing away with melee if not dead from toxin inside belly, also Feast Armor strips while they are in there. Runs out of energy fast after about 13+ enemies are eaten.. I've sucked up about 28 before meter starts jugging down and you will run out of energy in like 3 seconds.
Saves life support in belly, and Void Traces over time. Pretty good at fast run through exterminates, even Steel Path high level.
901 armor + 900 [Guardian Armor] + 50 armor per enemy in belly (600 for 12) = 1801 < 3000ish

If Umbral Forma's ever become common, then I will probably use them to build a [Primed Flow] version with just full fleeting and MAXED Umbral mods since you can buy those from Cephalon Simaris now.