Necroskitter reads: Whenever a creature an opponent controls with a -1/-1 counter on it is put into a graveyard, you may return that card to play under your control.
If a creature is destroyed, it dies and goes to the graveyard. Since Necroskitter says that the creature must have a -1/-1 counter on it, that counter can be from any source, and also can have more than one counter.
Once you cast Damnation the board will be wiped, you lose Necroskitter, but gain all the opponents creatures with -1/-1 counters.
In future, refer to any form of counter as a counter, as a token is a different entity.
January 11, 2015 5:04 a.m.
Yea, ty. Of course I meant counters, dunno why I typed tokens. Much love <3