A single, 24 year old man who took the job as a teacher in order to settle the two million yen loan his troubled friend conned him out of. Hayato wanted to quit his job when he found that the whole village is not normal, and that the students he was teaching were ninjas, (k. However Himawari's rescue from being run over by a train had changed his mind.

Hayato is one of several anime male leads (i.e. Rock of Black Lagoon) who doesn't fit in with the surroundings but manages to find a way to survive. For Hayato; it's his luck, his ducking ability when confronted with someone more skilled than him, and some of his students taking a shine to him. On top of that, Hayato has a good aim (as shown when he was throwing darts in a bar) and ridiculously keen eyesight.

Source: Wikipedia