Raijin

The father of Raicouda.  The son of a high-ranking delegator in his home clan, Raijin shirked ambition in favor of the arts, and loved to travel.  When he was selected as a sire for the Hybrid project, he took to the culture of his host clan with enthusiasm - even learning to hunt, and courting his way through the local bachelorettes.  

He quickly landed the heart of the dancer Chuva-Korra, who named their son after him.  Raijin, however, disappeared a few years later, and hasn't been seen since.