~8k HP if the purinfriend I use is good.
I suppose I can replace one of the orbchangers to my White Knight, but that would severely cripple my damage output too because combos are what are going to make this work.
I suppose I could use Arashi's Hermes too if need be-- that'll double my HP but also not make my ATK boost as high...
Doing a few tests in Endless:
Combining Verche, Drops, and Hermes' orb changes, Hellray Harpie Demon's 25% def decrease, and Pom Princess' light x2, I noticed that Hellray was able to do ~96000 damage. That should easily wipe out at least one of the will o' wisps. I didn't catch how much Hermes did, but I'm sure it was more than enough if you take weakness multiplier into account.