|First appearance||The Return of Tsul 'Kalu|
Tsul 'Kalu is a highly intelligent Bigfoot—or dogman-like bipedal cryptid. His first appearance was in The Return of Tsul 'Kalu.
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.
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.)
According to Cherokee legend, a widow wanted her daughter to marry a hunter, though the daughter herself loved a mysterious unseen stranger. One night the invisible stranger brought food to the daughter's mother, and asked for her daughter's hand. When the mother told her daughter to ask the stranger for wood, he brought them huge uprooted trees rather than logs and branches. Her mother was terrified and furious, saying that he must be some kind of monster, and the next time he came, he brought her nothing. Nevertheless, the daughter married the stranger over her mother's objections. and he lived unseen with them in their lodge, departing every day before sunrise, bringing home food and goods after sunset, and sleeping with his wife at night. When, after some time, the mother insisted on seeing him, he promised to show himself if the mother promised not to object to his appearance. By the light of morning, however, he appeared in terrifying form, gigantic of stature, very misshapen, and with eyes glowing and slanted like a fox's or cat's—whereupon the mother cried out, "Tsul 'Kalu! (literally, "He has them [i.e., his eyes] sloping!"). Tsul 'Kalu swore never to show himself to the daughter's mother again and vanished. Several months later, when the girl gave birth, Tsul 'Kalu returned to his wife in the night to convince her to come back to his new home with him. The next morning she told her mother she was joining her husband, left her village, and was never seen again.