From A Wiki of Ice and Fire
Grey Worm by Amok©
|Allegiance|| The Unsullied|
|Book(s)|| A Storm of Swords (Appears)|
A Dance with Dragons (Appears)
|Played by||Jacob Anderson|
|TV series||Season 3 | Season 4|
According to a semi-canon source, Grey Worm has absolutely no facial hair, though the hair atop his head is short and brown. He is stocky, of medium height and square. He has a serious looking face, on the edge of solemn. The Unsullied do not display much emotion. He is young, in his late twenties or so. 
A Storm of Swords
Grey Worm was chosen by his fellow Unsullied as the most able among them to become an officer. He was placed under the tutelage of Ser Jorah Mormont to learn how to command. When Daenerys abolished the Unsullied tradition of being given new names every day, Grey Worm chose to keep the Unsullied name he had when he was freed.
Grey Worm is among those present during planning for the attack on Meereen, Daario Naharis states that the Unsullied could take down the gates with axes since they consider boiling oil to be no more than a warm bath. Grey Worm responds that this is false; although Unsullied would not feel burns like men do, but the oil, would blind and kill, but give the Unsullied a ram they would batter down the gate or die. Daenerys Targaryen tells Grey Worm she will not throw away Unsullied lives. Later there is a plan presented to invade the city through the sewers; Daenerys includes the Unsullied as those she does not believe are appropriate for invading through the sewers.
A Dance with Dragons
Daenerys has Grey Worm order her Unsullied to travel in pairs when the Sons of the Harpy begin killing her soldiers. When Daenerys disappears on Drogon's back, Hizdahr zo Loraq attempts to order the Unsullied but Grey Worm and his men refuse to obey him. However when Ser Barristan Selmy goes to Grey Worm for his help in seizing control of the council, Grey Worm agrees to aid Selmy.
Quotes about Grey Worm
|“||I have no plans for Grey Worm's race or personal history to become important at this time, though I do reserve the right to change my mind. Sometimes the muse plays strange tricks on me. ||”|