SIREI

"Like it or not, from this day forward, I'm going to be your commanding officer. You can call me Sirei, or just Sir."

The principal and commanding officer of Last Defense Academy. To put it another way, a weird little robot that orders the members of the Special Defense Unit around. Under his command, Takumi and the others will be working to wipe out the mysterious School Invaders.

His name is an acronym of "System Information Reinforcement Exalted Intelligence." In reality, SIREI is an AI that hosts a digitized copy of the collective will of humanity, developed by the scientists of the Exodus Project.