The Welsh god of the underworld. The god Amaethon stole from him a dog, lapwing and roebuck with led to the Battle of the Trees, in which his forces were defeated. A tale in the Mabinogion relates how he persuaded Pwyll to trade places with him for the span of a year and a day. In this period, Pwyll defeated Arawn's rival for dominion of the underworld Hafgan. Because Pwyll also refrained from sleeping with Arawn's wife, they became close friends.
Gwydion, one of the nephews of Math ap Mathonwy, and brother of Arianrhod. He contrived Gilfaethwy's rape of the maiden Goewin, Math's foot holder. He did this by starting a war with Pryderi of Dyfed, stealing his pigs, and thus taking Math away on campaign. But he and Gilfaethwy doubled back and Gwydion forced the other women to leave Goewin with Gilfaethwy, who raped her. When she confessed this to Math, he levied as punishment on his nephews that they spent three years as animals, Gwydion as a stag, a wild sow, and a wolf, breeding each year with his brother Gilfaethwy who was hind, boar, and she-wolf. They produced three offspring, whom Math made human and raised at his court. Afterward, they were restored to the court. Gwydion raised Arianrhod's virgin-born son Llew Llaw Gyffes, winning for him his name and arms by tricking his mother, and created a woman out of flowers to marry him. After that woman, Blodeuwedd, betrayed Llew to his death, Gwydion restored him to life and turned her into an owl.
i also found Caer in there...it just amused me...so there ya go