Oh, it's really interesting what you said Astaroith !
It seems to me that :
Spoiler for 71:
that Kumagawa witnessed the same thing than Zen but was able to master it. This girl is maybe the incarnation of life in each being and since each being is unique she's different for each person. The spirit of life maybe ?
I'm a bit disapoint by the end. I would have liked to have some time for Medaka and Zen before the next battle
.
Oh yes, what medaka said about Zen and all ?