couple comments, although the thing sounds cool overall
first of all: WAY overpowered for the level you need to get it.... more like have completed every quest! it could be part of the new storyline like the astral schools
second (pushing on the first point): 650 health? what level are you? this school is clearly powerful, but just have done the non member quests and defeating a little boss..... heres what the stat could be like
mystery wizard: 9500 health the boss cheats like this: every time you attack, he summons a mystery minion with 3200 health. the minion does lots of blades and occasionally uses time spells. The wizard use time magic too. also if you use a trap on him he takes it off, and if you use weakness he takes it off, but he doesnt shield and doesnt attack much. then you get your first spell. and you have to have completed celestia, OH YEAH