You could make the Gaia spell MR-negates. I'm not quite sure what the justification would be, but it would make it more reasonable. A crazy thing you could add to it would be summoning of some vinemen as well. As in, the vegetation comes alive, some of it grabbing the enemies and some of it forming vinemen to finish them off.
good idea combining a buff witha summon or a damage spell with a summon.. at leat one should be in and this might be the best option.
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