this sounds a bit interesting, but i think it would work as a small group rp with definite endgoal. Something like "restoring the heroes" or "shattering the crystals so all can use skills" ....or something of the like. The idea itself is actually quite captivating....the heroes of old being captured and turned into crystals against their will is a definite dark twist and i like that. 

I'd love to talk more about this, because iseki stuff is one of my favorite genres. <3