Shortly after Allen meets Arystar and recruits him into becoming an ally, he met Tyki. The man lives a double life: his "white side" that is a carefree and goofy man of Portuguese descent who travels with humans that love to play poker, and his sadistic "dark side" that has a lust for blood and takes up his role as Noah's descendant (and therefore, one of the antagonists).

Tyki and his group suckers Arystar into a game of strip poker, winning literally all his assets, but Allen interferes and plays against them. He wins (with cheating learned from years spent with Cross), and Tyki gives him a pack of playing cards before his group departs.

The author gives the first hint that something is wrong when the group is revealed to have in their possession a chunk of silver with the name Kevin Yeegar on it - the name of the exorcist general that had recently been killed. In their next encounter, Allen meets Tyki's Noah side, and, after a talk, Tyki leaves him to die from a heart wound inflicted by Tease (a flesh-eating type of golem in the form of a butterfly) after destroying his Innocence, spreading out the same cards he had given Allen over the boy's body. After realizing that Allen's name would not come off the walls of the jail cell, he goes with Jasdero and Debit to find Cross.

Tyki's powers stem from his ability to selectively interact with his surroundings. This allows him to become effectively intangible, passing through all manner of matter as a ghost would, or walk on air.

His powers also have an offensive aspect, allowing him to phase his hand into his opponents' bodies and selectively interact with their organs (i.e. heart), crushing them or tearing them out without leaving any external wounds.
He also possesses the ability to reject the existence of space around an area he chooses, which essentially makes it possible for him to create a vacuum around anything he pleases (this ability was put to good effect against Allen, which allowed Tyki to suffocate him in their fight).

He usually attacks using his powers in concert with the flesh-eating Tease golems given to him by the Earl of Millennium. The Tease themselves are capable of multiplying themselves, becoming a large swarm to consume Tyki's enemies, or change shape to act as shields or throwing blades.
He was responsible for the death of Kevin Yeegar, one of the 5 exorcist generals, and has killed over 6 other exorcists himself, including Suman Dark (whom Allen had tried to save), Tina Spark, Gwen Frere, Sol Galen, Kazanna Reed, Chakar Rabon, and Daisya Barry.