The siren squeaked and swam faster, nearly dropping Bakubabe but tightening his grip on him so as not too. It wasn't long before he was too far out, and Denki was too tired, to swim any farther-and he had no choice but to watch his friend disappear into the night.
D: "DAMMIT!! UGHH-"
He sighed, as he swam back to shore, giving up..he felt..horrible..I mean, he just witnessed his friend leaving..just because he didn't save him on time..Ren was waiting on shore for Denki, when he saw that he didn't have Katsuki..he was heartbroken. He didn't have a crush on Katsuki or anything like that-but he cared about him.
D: "I-I tried-I couldn't catch up with that stupid Siren-"
"....I-It's fine."
You know it's not "fine" Ren.