Comment by Chloe on Kedamonotachi no Jikan - Chapter 32

Yup. That was heavily implied before lol. There were panels with older Hiro sleeping. The dog is tugging on him in the bath scene where Airi has a breakdown because he knows Airi needs him. Older Hiro observes it (we see him floating) and that's pretty much the moment he fully wakes up. I believe the younger Hiro was triggered by Airi beating Hiro because it reminded him of living under his mom. You see him being cute and innocent thereafter. The older Hiro in turn is pretty much always a control freak. But it's interesting that he tells younger Hiro "I was protecting you". Because, again, it seems like author-san knows their stuff. Older Hiro alter who's unfeeling and controlling is there to protect the "innocent and loving" side. It's sooo complicated *sigh*. I feel bad for him. Since there are 3 Hiro-kuns now, 2/3rds of him are very much redeemable lmao.

Oh and I'm pretty sure it was triggered by the amputation and he didn't have it before? At least there weren't any hints.