^ it is already foreseen when urobuchi states that he likes ryuki's plot.

Could it be that DJ is final boss? He seems like one for me

I don't know but I guess she is the 'chosen one' by the forest itself. Remember how the DJ says he wants to know who is the 'chosen one' between Kaito and Kouta or maybe someone else?

Maybe she can become a very powerful lockseed because she is the essence of the forest and is given to Kouta towards the end, LOL.

Sagara (Serpent)
Blonde Mai (Eve)
Genesis Driver
Project Ark

Helheim:
Helheim ("house of Hel") is one of the nine worlds of Norse mythology. It is ruled by Hel, the monstrous daughter of the trickster god Loki and his wife Angrboda.
This cold, dark and misty abode of the dead is located in the world of Niflheim, on the lowest level of the Norse universe. No one can ever leave this place, because of the impassable river Gjoll that flows from the spring Hvergelmir and encircles Helheim. Once they enter Helheim, not even the gods can leave. Those who die of old age or disease, and those not killed in battle, go to Helheim while those who die bravely on the battlefield go to Valhalla.
The entrance to Helheim is guarded by Garm, a monstrous hound, and Modgud. The giant Hraesvelg ("corpse eater") sits at the edge of the world, overlooking Helheim. In the form of an eagle with flapping wings he makes the wind blow.

either micchi maybe he ate the fruit and become overlord XD
or forever retard like the Club/ leangle rider    (no form at all, both are green-gold combo, grape also similar with club.)

wait...ryugen got kiwi form what. 

the only one don't have form is durian... because suit cant put armor lol..also see the design know already he is a joker role.