|Game||Tales of Vesperia|
|Occupation||Member of Leviathan's Claw|
|Japanese Voice Actor||Akio Suyama|
Zagi is an elite assassin Yuri Lowell meets early in the story. Deluded and somewhat insane, the party fights him a total of five times in the story. He is first encountered in Zaphias's imperial castle, where he mistakes Yuri for Flynn Scifo, though it is never revealed who sent Zagi to assassinate Flynn initially. He is defeated by Yuri, who also protects his new ally Estelle from Zagi's attacks. This defeat leads Zagi to develop a personal grudge against Yuri throughout the story. Zagi battles Yuri and his allies again on the ship leaving Capua Nor, incidentally preventing the party from pursuing Ragou and Barbos, who escape on an emergency boat.
He is defeated again and caught in the ship's explosion. However, despite his seeming demise, he returns yet again in Nordopolica's coliseum, interrupting a battle between Yuri and Flynn. In this encounter, he sports a seemingly-mechanical left arm equipped with a powerful bodhi blastia. He informs Yuri he was the one who gave this to him, meaning his arm was lost after the previous battle. The blastia allows Zagi to absorb magic artes but breaks when he absorbs too much magic, leading to his defeat.
Zagi appears for a fourth time in the control room of the mobile fortress Heracles. He attacks more fiercely than before, poisoning himself to add new attacks to his repertoire, but falls yet again to the party's strength. After his defeat, he returns and attempts to continue his fight with Yuri even after being shot out the window by Yuri's assault. However, before Zagi is able to do this, Yeager appears with Gauche and Droite, who force Zagi out the window once more.
Zagi's fifth and final appearance is in Tarqaron's destroyed coliseum. He blocks the party's progress with a seal that can only be removed by taking his prosthetic left arm, ensuring the party would fight him with their full strength. At this point, his physical appearance alters dramatically: his hair now drooped around his head, his shirt torn, bulging veins visible on his shoulder and chest, his blastia arm with a new design around the forearm, his voice distorted, and covered by a crimson aura. Nonetheless, Zagi is defeated for the final time. He comments that his body is greatly weakened and suggests to himself to convert his own body to a blastia as he struggles to stand. Yuri walks up to him and slashes him with his weapon, causing him to stagger backward until he falls off from the platform to his death.
In battle, Zagi uses two dagger-like blades, held in a reverse grip. He fights with various, fluid movements, such as spinning around and dashing upward or downward. He can also throw his knives like boomerangs. In later battles, his attacks can also inflict paralysis on their victims. Zagi carried a vial of poison with him when he attacked the group on the Heracles. However, he used it on himself, enabling him to blow poisonous clouds at his foes. Zagi's blastia arm opens a whole new range of abilities for him.
He can fire powerful beams from it or use it to shield himself from attacks. Doing so, however, leaves him exhausted and vulnerable to attacks afterward. In his final battle with the party, it also acted as a key to a magic seal blocking the party's path in Tarqaron. His mystic arte, Shining Blastia Field, blows his opponents away from him while he overloads the blastia in his replacement left arm. The overload shoots a beam of concentrated aer into the air, which proceeds to rain down upon the party. Coincidentally, he shares some of his attacks with Repede.
- Though not directly appearing in the game itself, Zagi is alluded to by Yuri in Project X Zone when the party confronts Vile from Mega Man X for the final time in Chapter 37.
- Zagi also appears in Project X Zone 2 as a boss unit starting in Chapter 22 when Yuri and Flynn rescue Estelle from M. Bison from Street Fighter II.
- In a skit viewed in the City of the Full Moon, deep within the Necropolis of Nostalgia, the party entertains the possibility of Zagi being a Child of the Full Moon on the basis of his hair color.