It seems that the Deep Sea King was ONE's favorite monster, maybe that's why he made Jachi in Versus.

>--There are a lot of heroes and monsters in the anime. What is your favorite character?

>ONE: I think my favorite after all is Saitama. Besides that, my favorite hero is King, and my favorite monster is the Deep Sea King. Specially when the Deep Sea King became larger in the story, it was very fun to draw it.
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