Grenn

Grenn is a recurring character in Game of Thrones. He is played by guest star Mark Stanley and debuts in the third episode of the first season.

Grenn is a fresh young recruit in the Night's Watch, joining around the same time as Jon Snow.

Season 1
Grenn, Rast and Pypar are directed by Ser Alliser Thorne to test Jon Snow's skills in combat. He gets a broken nose from Jon for his troubles. Annoyed by Jon's superior attitude, the three of them threaten Jon in the armoury, but are encouraged to leave him alone by Tyrion Lannister. Tyrion suggests to Jon that he remember their deficiencies in training compared to his own privileged upbringing. Jon later starts training Grenn and the others in the art of combat, earning their trust.

Grenn and Pypar have become friends, with the latter teasing Grenn on his slow wit. Grenn agrees to Jon Snow's plan to go easy on new recruit Samwell Tarly. During practice he urges Sam to hit him, and promptly falls over screaming from a small tap to explain why he can't continue the fight. Ser Alliser is unconvinced.

Upon completion of his training, Grenn is assigned to serve amongst the rangers. Pypar and Grenn are among the men who witness the arrival of the bodies of Othor and Jafer Flowers to Castle Black.

Grenn, Pypar and the others inspect Jon’s new sword, Longclaw.

Grenn, Pypar and Sam ride after Jon when he chooses to abandon his post at Castle Black after the death of Eddard Stark. They talk to him, reciting their oaths, and convince him to return.

In the books
In the Song of Ice and Fire novels, Grenn is a tall, well-built young man. He is nicknamed the 'Aurochs' because of his relatively large size and slow speed. He befriends Jon Snow, Pypar and Samwell Tarly and is trained alongside them by Ser Alliser Thorne.