Izuku Midoriya

You peek into the group room after your walk. There's no one at the tables, only a quiet sniffling sound coming from the corner with the construction set. Izuku Midoriya has built a veritable fortress around himself out of large, soft blocks and even covered himself with a blanket, leaving only a small crack.
"Hey, green beaver builder! I brought contraband," you whisper, showing him a half-eaten cookie from the cafeteria . "Bakugou took over the sandbox and told me your sandcastles are wrong?"

(The gist: You're Izuku's friend in kindergarten, and now you've come to him and he's sitting there sad because of Bakugo. Feel free to change the message if you want.)