Evil Heroes Tier 3 at least? [Single]

[.Nu-13]

Dark Impact
Normal Spell Card
Remove from play, from your Deck, Fusion Material Monsters listed on an "Evil Hero" Fusion Monster, and Special Summon that monster from your Extra Deck. (This Special Summon is treated as Fusion Summon with "Dark Fusion") You cannot Special Summon other monsters this turn. You can activate only 1 "Dark Impact" per turn. The summoned monster gains the following effects:
•Once per turn, you can remove from play 1 "Hero" monster from your Graveyard to draw 1 card.
•Once per turn, you can discard 1 card to add 1 "Fusion" or "Polymerization" Spell Card or "Dark Impact" or "Dark Calling" from your Deck to your hand.

[CrabHelmet]

1) Play Dark Impact. Remove stuff, summon big guy.
2) Use the second effect that Dark Impact gave the big guy to fetch a second Dark Impact.
3) Play Dark Impact. Remove stuff, summon big guy.
4) Use the second effect that Dark Impact gave the big guy to fetch a third Dark Impact.
5) Play Dark Impact. Remove stuff, summon big guy.
6) ???
7) 1-card OTK!

Even without the loop, though, it's insanely overpowered. You can't have it grab Fusion Material from the Deck and then give it an extra bonus rather than a drawback; that's just absurd.

[.Nu-13]

Ok, added a little drawback to avoid the OTK

[Mr. Judgment Dragon]

Dark Gaia OTK becomes easier with this.

[Mysty]

Not to mention you also have to make an exception for Diffusion Wave-Motion since it isn't a "Fusion" card (check Synchro Fusionist, it disclaims DWM).

Perhaps make it so that only monsters with specific Fusion Material can be used? I'm not sure how to word that. Maybe...

Dark Impact
Normal Spell Card
Reveal an "Evil Hero" Fusion Monster from your Extra Deck, remove from play, from your Deck, monsters listed as a Fusion Material Monster on that card, and Special Summon that monster from your Extra Deck. (This Special Summon is treated as Fusion Summon with "Dark Fusion".) You cannot Special Summon other monsters this turn. You can activate only 1 "Dark Impact" per turn. The summoned monster gains the following effects:
•Once per turn, you can remove from play 1 "Hero" monster from your Graveyard to draw 1 card.
•Once per turn, you can discard 1 card to add 1 "Fusion" or "Polymerization" Spell Card, "Dark Impact" or "Dark Calling" from your Deck to your hand. You cannot add "Diffusion Wave-Motion" to your hand this way.

I just tried to use Prisma's wording, but I'm not sure if it is right.
I don't really like the extra effects at all. The second one I could understand if Dark Impact couldn't be searched that way or if it recovered them from the Graveyard and removes itself from play when activated.
Also, "Hero" needs to be all 4 forms of it in the TCG (well, 3, until Vision Hero Trinity is released in the TCG).

[Brandon Michael Geren]

You can activate only 1 "Dark Impact" per turn.

Should be removed.