I feel like imagining the climax of the manga already: Shikanoko, being some kind of deity, fucks around and decides to abadon her friends. The deer club + council members + Tsuchi + Ukai-sensei all come to bring Shikanoko back to her senses. Shikanoko does return but realizes she may not have much time cause her "mission" is almost complete. The final arc is Shikanoko's final days as both a high schooler and a deer club member. She is not human but her experiences at school make her one. She tearfully bids farewell to the main cast and dies, only to be reincarnated as Shikanoko, but without antlers, the final pages is mirroring the very first scene: Shikanoko 2.0 goes to school, but now passes by each of the main cast, all grown up and they silently acknowledge her. The end