Key Attribute: Strength.
Unarmed Combat is a physical skill that allows characters to engage in hand-to-hand combat without the use of weapons. With a successful Unarmed Combat check, a character can deliver powerful blows, dodge attacks, and use their surroundings to their advantage. This skill is also used to disarm opponents, use environmental objects as weapons, and perform acrobatic feats. Characters with high Unarmed Combat skills can also use their opponents' momentum against them, create complex combinations of attacks, and use their surroundings to gain an advantage.
Unless any other rule states otherwise, your damage die for Unarmed Combat is a d4.