You might want to look at adding red for seething song and the other red ritual, i forget the name, to allow you to speed the deck up a bit, and chromatic stars for card draw/mana conversion to the colors you need.
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for casual, it looks like a lot of fun, but for tourney play, you probably want to slim down to 2-3 colors. I like Green/White, maybe splash Blue for some card draw.
Played since Unlimited, only found the site by chance. love it!
neeldebite is ok, but you might think about running consume spirit or some other straightforward lose life/gain life spell.
Seems like there's a lot of late game stuff, but your early game is pretty thin.