Kerchak is lion-hearted, mighty, and faithful. He cares a great deal about the gorilla family he leads, but his cold disposition gained after the demise of his son causes those he loves to fear him. Kerchak has a great hatred-like fear of outsiders of any kind as well, reacting aggressively when they are near. He is not without a heart, however, kind and almost loving to those he trusts, even outsiders that have gained that trust.
In Kingdom Hearts, Kerchak is leader of his gorilla family, taking great care of each member. He has a severe distrust of strangers of any kind, as seen by how harshly he treats Sora and his companions. Once he learns he can trust Sora after Clayton's defeat, however, he grants the Keybearer and his companions access to the waterfalls, as Tarzan was requested previously.
Kerchak is a large, adult male gorilla with black hair and grey skin. His forearms are enormous and his head is rather large. His eyes are brown and small in comparison to the rest of his head.
When Sora, Donald, and Goofy meet Kerchak, his distrust of outsiders causes him to treat them rather coldly. He even ignores Tarzan's request to take them to the waterfalls. But after Sora and company save the pack from Clayton, he lets them into the waterfalls, where Sora seals the Keyhole of Deep Jungle.
Kerchak makes his film debut in Disney's 1999 film, Tarzan. Leader of a large family of gorillas, he is also a caring and devoted mate and father, heartbroken when his only offspring is killed by the leopard Sabor. When Kala brings the orphaned Tarzan into the family, Kerchak immediately orders her to take him back out of his fear of humans, also saying that he couldn't replace the child they had lost.
Kerchak eventually and reluctantly allows Tarzan to stay in the end, not willing to consider the boy his son. His dislike of Tarzan only grows as the boy ages into a man, causing much conflict in the young Tarzan. When Sabor is killed by the boy, a slight respect is sparked between the two as the leopard's body is offered to Kerchak.
However, this quickly evaporates when an encounter with the gorilla family and the humans Jane, Professor Porter, and Clayton is made possible by Tarzan and Kerchak aggressively attacks the humans in order to protect his family, forcing Tarzan to fight the gorilla off due to the bond that has developed between him and the humans.
Kerchak's great might strikes Clayton's interest, however, the man attacking the gorilla family with a band of thugs. Tarzan returns and aids Kerchak, however, Clayton defeated, but not before the hunter shoots Kerchak. Tarzan approaching the dying gorilla, Kerchak makes amends with the boy, making him his successor and finally accepting him as his son.