Melus

Melus is the older of Navia's two attendants. During the events of Deluge of Wrathful Waters, Melus was dissolved by the Primordial Sea while trying to save other people when the water began flooding Poisson. His consciousness was forged into an Oceanid, where he and Silver protected Navia from the collective of other Poisson victims after she nearly fell into the water, who wanted to absorb her consciousness. The act was long enough for Neuvillette to save her from being completely dissolved, where he gave his final farewell to her. Source: https://genshin-impact.fandom.com/wiki/Melus