Ruby Crystal Blossom
"Every Epoch, i.e. every ten thousand years, the Ruby Crystal Blossom will develop a core where its soul nurtures the natural energy and transforms itself into a plant monster.
It takes ten years for it to get full control over its body. Until then, it is just like any other monster without any consciousness on its own.
And this is where things get interesting. During the first six months, its soul will still be in its core and won't be integrated with the rest of its physical body. And if anyone managed to kill it and absorb the core completely, they can transform into their own Arcana spirit.
A Mono Arcana user will become a Twin Arcana user and a twin Arcana user will become a triple Arcana user. Of course, even in such a situation, one needs proper guidance or else, it will swallow the existing Arcana as it was a platinum grade spirit.
I think this is probably the reason those kids are here."