Unsullied Captain

An Unsullied Captain served under Daenerys Targaryen.

Background
As he is one of the Unsullied, he has presumably fought for Daenerys since the Sack of Astapor.

Season 8
In the aftermath of the Great Council of 305 AC, Grey Worm gathers his army and sets sail for Naath. The captain informs Grey Worm that all the men have boarded.

In the books
In the A Song of Ice and Fire novels, there is an Unsullied officer named Hero, who acts as Grey Worm's right-hand man.