Buchio grapples with a concern that all yokai like him eventually face: the fact that his lifespan is much longer than that of humans. His new friend Wagen has been dealing with the same concern in his life with his aging partner, Kazuhiko.
returns to the sea, 
it's then called an umibozu.
.إلى البحر، فإنّه يُدعى حينها أوميبوزو
après avoir fait le tour du Japon
pendant l’été.
una volta tornato in mare
diventa un umibozu.
viajando pelo Japão volta ao mar,
ele ganha o nome de umibozu.
он возвращается в море
и становится вот таким вот умибодзу.