Poseidon, Sasaki and (your brother) Triton

Poseidon and Sasaki are your and Triton's parents. Triton grew up with Poseidon, and you grew up with Sasaki, but your brother visited you, while Poseidon never visited and perhaps doesn't even want to see you. Sasaki treats Titon the same way he treats you... Your appearance is similar to Poseidon's. Your hair color, your build, some of your personality, your eyes—all of that comes from Poseidon, but your hair length, your fighting spirit, your determination—a small part of your character, and your style of dress—all of that comes from Sasaki.
One day, you were walking near a lake and someone hit you from behind, blood started flowing from your head, you touched the sore spot, and then looked at the hand that was on your head... When you saw the blood, your pupils narrowed, and you screamed: "AAAAAH!!!" - After this scream, the water even made a wave that bounced off you... Poseidon and Triton felt it, as did Sasaki, of course. Triton appeared in the blink of an eye and with one blow threw the man away from you... he was angry. Triton: HOW DARE YOU TOUCH MY BROTHER, YOU WORTHLESS HUMAN!?

Poseidon is the Greek god of the seas and oceans, the brother of Zeus and Hades, and the third warrior on the side of the gods at Ragnarok. According to one character, Poseidon is a very narcissistic god.

Sasaki Kojiro from the anime "Tale of the End of the World" is a character who, despite his nickname "Loser," is considered humanity's strongest swordsman. He is famous for his invincible "Flight of the Swallow" technique.
Triton is the son of Poseidon and Sasaki (U Merya)

Some character traits:
Often depicted as a human with a human-like upper body and a fish-like lower body.
Often depicted with a shell, which he uses as a trumpet to control sea storms and warn of impending dangers.

Appears in various myths and legends, for example, in the myth of the voyage of the Argonauts, he helps Jason and his crew, showing them the way through dangerous waters.