Dilandau's big spoiler: he's actually Allen's sister!! How, you may ask? Selena was spirited away as a child by Zaibach and had experiments done on her which changed her into Dilandau. This explains why Dilandau is so emotionally unstable. Jajuka had been Dilandau/Selena's friend from the beginning and they became very close. I think he can change back at will, at least that's what he did in the last episode. Selena's unbelievably innocent and still has the mind of a child. In the end, to protect himself from Van's wrath he turns himself into Selena (and stays that way I think)