Imbu seems to run the computers at Battle School. The only reason we know his name is because he and Graff discuss what the heck the mind game is doing with Ender’s mind. (You program a computer to play mind games on kids – what do you expect?) Imbu helpfully lays out some ideas about what the mind game might mean to Ender, but he can’t answer Graff’s questions about the program. So maybe he should’ve been a psychologist instead of a computer guy...