Tretista Kelverian

Tretista Kelverian (トレテスタ・ケルベリアン) is one of the bosses in Mega Man Zero 3. Tretista is based on Cerberus, the three headed hellhound. He is one of the Eight Gentle Judges, and has three independent thought circuits that he uses to reach a fair judgement. When Dr. Weil brainwashed him to be one of the Weil's Numbers, he could not think properly, becoming violent and arrogant. During a mission, Zero went to investigate a giant elevator created by Neo Arcadia, and he finds Kelverian protecting it, fighting against him. Zero then discovers the elevator is used to transport mass amounts of E-Crystals to be used as energy. Kelverian reappears in the final stage, but is defeated again by Zero.

Tretista attacks by separating the dogs attached to his shoulders which then jump around the room, throwing a box and then dashing to destroy it, spitting vaporous energy balls across the floor, and bending a metal bar into a V shape and then tossing it like a boomerang. At A or S rank he will use his EX attack, where a large laser occasionally comes from his claw when he dashes to the box. Defeating him gives Zero the Absorber Body chip and, if at A or S rank, the Gale Attack ability.

An image of him appears in Mega Man Zero 4 as one of Dr. Weil's first form attacks, where he tries to smash Zero.

Data
Nickname: Rabid Dog Protection (咬哭の守護 Koukoku no Shugo)

EX Skill: Laser Claw (レーザークロウ)

Tretista Kelverian drops a large crate on the ground, then generates a large, purple energy blade from his claw and rushes forward to destroy it.

Mission: Search Facility

Zero's EX Skill: Gale Attack (Reppuugeki)

Stage enemies
Enemies in Tretista Kelverian's stage.
 * Sub-boss: Spearook
 * Batring
 * Cattatank
 * Eye Cannon
 * Flopper
 * Pantheon Guardian
 * Pantheon Fist
 * Shotcounter
 * Shotloid

Trivia

 * Tretista comes from tretesta, which means three-headed in Italian, and Kelverian (Keruberian) is a play of Cerberus (Keruberosu), making his name "Tretesta Cerberian" or "Tretesta Kerberian".
 * Coincidentally, Tetrista's appearance is similar to that of Omega's second form, in that they both have heads attached to their shoulders instead of closer to the middle head.
 * Tetrista and Childre Inarabitta are the only members of the Weil's Numbers that first appears to Zero already morphed in their Punishment forms. He only assumed his humanoid form briefly during the final stage, morphing afterwards.
 * The boss Bifrost from Mega Man ZX Advent has an appearance that is quite similar to that of Tretista. Both bosses also have similar standing animations, and both have an attack that sends a rolling weapon across the floor.
 * Tretista breaks the tradition of having two life bars as one of the eight main bosses in the Mega Man Zero series, having a third bar and surpassing the other judges' health.
 * His three heads having a different thought system for judgement could be a reference to the three judges of Hades Rhadamanthys, Aeceus, and Minos.
 * He says hes the guard dog of Hades which can make sense since "Cerbures" the actual guard dog of Hades has three heads.