Green clone concepts.

This was the first design I came up with. I asked the question of why would green have a clone? I thought of a species going extinct, and a new species being introduced or evolving and adapting to fill that niche. I thought beast was a good creature type (even though it'd change upon ETB) because it's flavorful of a species changing over time. Green gets graveyard versatility, and I think checking your graveyard for a creature that died supports the aforementioned flavor and doesn't intrude upon black's slice of the color pie (unless someone really wanted this design to be UB).

It could be argued that the 'survival of the fittest' principle would state that the creature died didn't fill a proper 'niche' and was 'unfit', but whatever.

Mechanically this seems quite to me. It has this old style Reincarnation vibe, but IMO these days it looks like Grim Return more than anything.

White also gets to undo the death of a turn as a 'miracle' of sorts e. g. Angelic Renewal, Adarkar Valkyrie, Faith's Reward.

I actually would be tempted to call this Returned Hero and put it into white with a "it's a Spirit in addition to its other types" clause.