Ultimate Nullifier
Equipment, 2
You may discard a Heralds of Galactus character card rather than pay Ultimate Nullifier's recruit cost.
Remove Ultimate Nullifier from the game >>> Negate target effect an opponent controls. Use this power only during the combat phase.
You can target any effect controlled by an opponent during the combat phase, including plot twist effects, payment effects, triggered effects, and power-up and reinforcement game-based effects.

INCLUDING those types of effects. Not an exclusive list. Can it nuke an ongoing effect? For example, could it get rid of Klaw (1)'s "cannot ready" thing? I mean, pretty much everything that happens in-game is an effect of some sort...

Man... this set is a rules headache. @_@

if it puts an effect on the chain, then you can negate it. if it is a Continuous Modifier then no.

Klaw's "cannot ready", Doomstadt's +3 ATK/DEF (version depenant) or Considered to control Doom, and the like are Continuous Modifiers, and do not use the chain, so no

I can't seem to locate the FAQ on UDE's site. Someone wanna point me in the right direction, please?

here you go
Link

Cheers. I'd rep you, but I need to spread my love around.