I like this idea a lot but, I think it would work better with +1/+1 counters instead of -1/-1 counters.
Persistence (If this creature was cast from your hand this creature enters the battle field with a +1/+1 counter on it. If this creature dies and has a +1/+1 counter on it, return it to the battlefield under its owner's control.)
For balancing a number could appear after the ability like Bolster has.
Persistence 3 (If this creature was cast from your hand this creature enters the battle field with three +1/+1 counters on it. If this creature dies and has a +1/+1 counter on it, return it to the battlefield under its owner's control.)
Further more these creatures could have evergreen abilities contingent on them having a +1/+1 counter on them like [[Lightwalker]] does. "Lightwalker has flying as long as it has a +1/+1 counter on it"
Doing the ability this way would allow the creature to come back multiple times, as long as the player can get a +1/+1 counter on it before it dies.
My idea for a card with this mechanic would look something like this:
Resilient Rakshasa 3BG
Creature - Cat Demon
Resilient Rakshasa has deathtouch as long it has a +1/+1 counter on it.
Persistence 2 (If this creature was cast from your hand this creature enters the battle field with two +1/+1 counters on it. If this creature dies and has a +1/+1 counter on it, return it to the battlefield under its owner's control.)
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Or
Resilient Rakshasa 2BG
Creature - Cat Demon
Resilient Rakshasa has deathtouch as long it has no +1/+1 counters on it.
Persistence 2 (If this creature was cast from your hand this creature enters the battle field with two +1/+1 counters on it. If this creature dies and has a +1/+1 counter on it, return it to the battlefield under its owner's control.)
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