When Shinsenbou meets Goki for the first time, he thinks that now that Goki has awakened inside Akira, Akira is gone and only Goki is left inside him. Shinsenbou tells Goki about this and Goki tells him about all the fond memories of his life as Akira, which involves his almost sibling-like relationship to Shinsenbou, who acted like a big brother towards him.
We can see Akira armwrestling with Shinsenbou, telling him about his worries, being carried around and playing catch. Goki then reassures that he is now both Akira and Goki. This leaves Chiaki and Shinsenbou rather confused, but when Goki tells them that everything is fine, Shinsenbou feels the relief and starts crying manly tears of joy.