okay. i always thought that nissa's first walk to lorwyn is an interesting design space. This is a bit of a stretch lorewise but i think it'd be fun to play with. Also, G/B group hug is a woefully unexplored edh decktype and Nissa shouldn't just be the "elf 'walker," especially now that Freyalise exists.
Legendary Creature - Elf
Whenever Nissa, Child of Joraga deals combat damage to a player, add GG to each player's mana pool.
2GG: Exile Nissa, then return her to the battlefield transformed under her owner's control. Any player may activate this ability.
1/2
[Nissa is curious but not bloodthirsty, at least at first. She also ignited her spark at a very young age, hence the easy and straightforward transformation method.]
Nissa, of Nature's Perfection (Green/black)
Planeswalker - Nissa
+2: Each player gains life equal to the number of Elves you control.
-2: Each player sacrifices a non-Elf creature they control, then adds G to their mana pool equal to that creature's converted mana cost at the beginning of their next turn.
-8: You get an emblem with "Whenever you gain or lose life, each opponent loses that much life plus two."
3
[as a planeswalker that could drop as early as turn three, Nissa can't be too powerful, so I made her "drawback" be a heavy thematic focus on each player effects. Everything she does has a mind for the overall balance--ecology--of the game. Instead of winning the game for you outright, Nissa manipulates the environment in ways that tilt the game in your favor and in general plays politics without becoming a massive target--which is a very black, Lorwyn-elves thing to do. She discourages her own destruction, encourages combos and exciting plays with her loose attitude toward green mana, and finally has a nice and permanent global Sanguine Bond effect as her ultimate. The ultimate itself is a bit of a trick--on first glance it seems to encourage a sudden change from group hug to "everyone attacks you, all the time" but not only would this further discourage any damage being directed at you/Nissa (everyone wants the ultimate to go off), but after all, you don't actually have to activate the ultimate.]
Her creature form can be played in any deck for mana ramping, but her planeswalker form (after having experienced Lorwyn's elves) is slightly more tribal. There are some games where she will never transform at all, and games where she will transform on your third turn, and in each situation, she can fulfill the role for which she's needed, either as a pseudo-mana dork that chips away at your opponent or as a huge and intimidating (but not OP for the third turn) planeswalker. Her life-gain effect works better in the late game, her mini-pod effect is usable any time for crazy ramp all around, and her ultimate will be a much larger part of games than just "that crazy amazing mythical bomb that never actually happens." She's effective in two-player too, of course.
I'm really proud of this one