WARNING: The following contains spoilers for My Hero Academia Season 5, Episode 16, "Long Time No See, Selkie," now streaming on Funimation, Hulu, and Crunchyroll.
My Hero Academia has a history of its characters' personalities being influenced by their physical appearance. Big, burly men like All Might and Endeavor are stoic and tough, while the girls in Class 1-A are feminine and generally soft-spoken unless Mineta is nearby. Season 5, Episode 16, reintroduces a character who's not constrained by the typical archetype associated with his commanding presence. Selkie, the Sea Rescue Hero, is big, tough, and just wants someone to agree that he's cute.
Captain of the Oki Mariner, Selkie is a 6'4" walking bicep. His Quirk allows him to do anything a Spotted Seal can do, and even a few things they can't. He uses his superhuman strength to propel himself through the water at tremendous speeds, and though he doesn’t breathe underwater, he can hold his breath for quite a while. Selkie's Seal attributes allow him to survive cold water as well. Unlike a Spotted Seal, he uses his sonar capabilities to track people as well as a substitute for his eyesight in combat.
Selkie is a stern teacher, a skilled fighter, and relentless in his pursuit of villains. The character could have easily been just a water-type alternate form of Endeavor, but he avoids the stoic tough guy trope altogether by constantly posing in an attempt to be cute -- though his sidekicks seem to find this habit annoying, and decidedly not cute. Selkie does acknowledge that his posing may not be very successful, but he keeps trying anyway.
Many characters in My Hero Academia, even the students, have a habit of taking themselves too seriously. It's refreshing to see someone like Selkie who is an extremely capable hero but also has a quirky personality to go with his Quirk powers. He gets along well with Tsuyu, as they both have pretty simple Quirks of doing anything a particular species of animal can do. This camaraderie also leads to Tsuyu being one of the few people who actually does think Selkie is cute.
Selkie also seems to be one of the only heroes, or adults in general, who recognizes that kids need time to have fun. In Season 5's filler episode, he encourages Ochaco, Tsuyu, and the others to have a beach party while they wait for nightfall when the villains will be on the move. It's easily overlooked that the students at U.A. are still children, and having fun is important to their growth. Shoto and Bakugo's social skills are proof of what happens when a kid is serious all the time.
The Sea Rescue hero is too intriguing of a character to be relegated to a supporting role in a filler episode. Selkie has an interesting kinship and dynamic with Tsuyu, who doesn't get enough credit for being one of the better heroes-in-training of Class 1-A. His outright refusal to be a cliché based on his appearance with his determination to be cute makes every moment he is onscreen endlessly entertaining. My Hero Academia should always make time for a grey behemoth who will talk about how cute he looks as he punches someone clear into next week.