The First-Grader

Watch out, teachers! On your guard, classmates! Take cover, school! I made it out of the Abyss, bringing a relative of mine back with me and acquiring great power along the way! Now I'm ready for the next phase of my life. Experimental elite school, here I come! I'm a first-grader, and I have nanomachines inside me. What did you expect? Great deeds? Oh, there'll be plenty of those! After all, it turns out this is no ordinary school....