Taiga - S1.E12

Gonza and Zaruba reflect on Kouga's growth as a knight, remembering him training with his father, Taiga. Out one night with his father, they encounter a Horror, with Taiga becoming Garo to destroy it. Later, Kouga witnesses his father dying at the hands of what he thought to be a Horror, though it is actually a figure named Barago. Kouga trains for years to be able to use the Garoken and fight as the new Garo, eventually becoming the man he is today.