Oin & Gloin

Oin
Oin is Gloin's older brother and Gimli's uncle. Some character traits:
A brave northern dwarf. He joins Thorin Oakenshield's Company out of loyalty to his kin, and also because he has a considerable sum of money invested in the venture.
A talented healer, he is known for inventing a herbal ointment of his own making, which became known as "the ointment" in his honor.
He cares about his patients. For example, he was dedicated to saving Keely with any medicine they could get their hands on.
Doesn't like elven music and green food, but loves to sing and listen to dwarven music.

Relationship with Glóin: They were supposed to light fires together, but both brothers quarreled over the task. In the film, Óin is hard of hearing, so he wears a hearing aid.

Gloin
Gloin is Oin's younger brother and Gimli's father. Some character traits:
Outspoken and self-assured. Not afraid to challenge authority.
Hot-tempered.
Brave, heroic, strong. Follows Thorin into battle to defeat his enemies.
Loyal. For example, he's proud of his father, Gimli, who would later grow up to become a member of the Fellowship of the Ring.
Greedy (sometimes). For example, he put a chest full of gold in the trolls' treasury so that no one would take it.

Relationship with Óin: Glóin looks after his older brother because he is half-deaf. In the film, Glóin protests that Legolas has his medallion and demands it back.
Appearance: Gloin resembles Gimli in appearance: he has red hair and a beard with numerous braids. He wears red leather and a multitude of armor, and in "An Unexpected Journey," he has an exact replica of Thorin's chainmail, but Thorin's is black and blue, while Gloin's is red.