Ren is gonna be fine Peterrrrrr-trust me-even if you can't hear me-:D
Um except Peter was still trapped in Katsuki's circle my dude. So he was now trapped-in the woods-with a Katsuki-who he had just sicced wolves on-who is the fucking KING of the FAE REALM-and Ren isn't there to protect/save him-AND he just agreed to stay with Katsuki as long as Ren was safe-spelled or otherwise(but probably spelled because of lore tings so yeah-)