Tsul 'Kalu is a highly intelligent Bigfoot—or dogman-like bipedal cryptid. His first appearance was in The Return of Tsul 'Kalu which season 2 of 2009 TV series called The Secret Saturdays. He's called "the Great Hunter" and has honor and respect for the hunt. Tsul 'Kalu uses an artifact made of the bones of the thunderbird to focus his powers; he must somehow have come across one in his hunting periods. Tsul 'Kalu is also the eighth "Beast of the Fifth Sun." It is revealed in the episode The Return of Tsul 'Kalu that Doc's blind eye was caused by a fight with Tsul 'Kalu. Doc won and Tsul Kalu gave him the hand as a prize of respect. When younger, Zak had destroyed the Judaculla stone in an accidental rockslide. Tsul 'Kalu tracked the Saturdays, until one night he stopped Doc in the HQ. They decide not to disturb Zak, instead going to the roof to solve some issues. Later on, Tsul 'Kalu came back for his "hand," to get it out of Kur's grasp. Finally Zak and he have a fight, during which Zak experienced flashes of Tsul Kalu's worst fear: Kur destroying the world. Zak won and, realizing that he could respect him, Tsul' Kalu let him keep the hand despite the boy's offer to return it, thus becoming the Saturdays' ally.
Tsul 'Kalu seems to have prior technical knowledge of human hunting devices. He has sported with a crossbow, blowdart, tomahawk, and a flute-like object that can produce sonic waves. He is also more associated with humans than cryptids.
In War of the Cryptids, he appeared again as Zak's ally, fighting mostly against Munya. He seemingly killed Munya with his ax at the end of the episode.
His eyes and claw glow white when he uses his powers in a similar manner to Zak's orange glow when he uses his powers. (The claws glow as well as the eyes because they are both focuses of power.)