I. I. R.E.

Short words like that are very useful for, I think cross word builders. Fuss, kerfuffle, trouble, dizzy, hubbub, bruhaha, or Ballyhoo. It's the sort of thing you would read in a book that would cover up in a book. So it needs an S on the end or an ES on the end. Because it's the third person, the answer is the third person.