BLACK PUMPKIN BOMBS OF FEAR: Demogoblin can use Energy Explosion. When he does, hit characters modify their defense value by -1 until your next turn.

REPENT!: When Demogoblin hits an opposing character, that character's controller chooses one: give that character two action tokens; or that character's defense power is countered until your next turn.

Just wanted to make sure this works.

Can I use the effects of Repent and Black Pumpkin Bombs at the same time?

So I can use energy explosion, hit a group of figures, each hit character now modifies their defense by -1 and also gain the effects of Repent to those that apply?

Repent! says "When Demogoblin hits an opposing character" and doesn't qualify it further. They'll work together.

So if I hit a group of opposing characters with Energy Explosion, each figure would suffer the effect of Repent? Each figure would either have their defense powers countered or have two tokens placed as applicable?

My bigger question would be, can you removed the damage reducer before damage from energy explosion is applied? it just says "When Demogoblin hits an opposing character", not after actions resolve or anything like that.

I would say not. I'd think you'd have to resolve one power before the other, though I could see being able to resolve their effects as though both powers are happening in conjunction with one another instead of as two separate game effects with sub-effects to deal with.

I don't see why not.

Seems pretty clear that as long as you hit them, it takes effect. So yeah, if you hit a group of figs with EE, they would all suffer from Repent. I'm not even sure you'd have to do any damage.