best guess he mentally cracked and now in his head any girl with similar circumstances reminds him of her and seeing her calm expression in death means to help those other girls he should kill them
considering how the box was explained to hypothetically be MC's Earth | 1st Wall | Alt Earth | 2nd Wall| Room. I assume it could release him into the Alt Earth. Then you can build your own Green Box on that new Earth and repeat
something that could explain it is that while her mana regen is high she has next to no mana pool to start up simultaneous spells and the armor fixes that by acting as an external storage, but still ofc the issue then comes up of why not use the regen to feed the armor or just chain spells one...
maybe he lost the backing of his household god or it straight up disappeared since so far it is somewhat implied the household (store) god of Nobu is responsible or has a strong hand in the connection
is this a miracle or something? did d.gray-man become a quaterly? either way this has made my day much better
also that was one heck of a bomb drop by Nea because we gotta bully Allen some more
without the pressure of the situation it's easy to see a mile away that girl was tricking him just to the simple fact that crimes are perfectly legal and encouraged and she admitted she had previously escaped the game
actually sorta curious as to these manga to avoid them, since it really sucks to start a manga then get news that it gets axed and gets a rush job ending or perpetual cliffhanging, which very few manga can pull off a rush ending
this arc/end definitely does feel rushed, quite possible author thought he had more time, but the publisher gave an unreasonable deadline so we got the quick and dirty conclusion to whatever this was
@exystence
on the credits page lower right corner TL had a small mention means something closely to "By Divine Edict. Let this servant serve even in death" aka it'd be a talisman you'd typically see attached to a Jiangshi (Chinese vampire zombie)