Eskel had a head of black hair. A massive scar marred his face. Similar to Geralt, he liked to count on the "Law of Surprise." The "Law of Surprise" was where he had gotten his horse, whose name was Scorpion.
As for the scar on his face, there was a backstory for it.
Eskel got it when he was trying to save the life of a prince, 70 years ago. He had invoked the Law of Surprise for his trouble, and at that time, the prince did not know that his wife was about to give birth to a female baby—Deidre Ademeyr. Even so, Eskel had yet to bring back his promised child.
As if by the hand of retribution, not doing so had brought him many troubles 20 years later, even causing him to make an enemy out of the sorceress Sabrina. This had angered Princess Deidre Ademeyr, who by logic would be his "granddaughter." She had slashed him across the face, scarring him for life.