Tretista Kelverian (トレテスタ・ケルベリアン Toretesuta Keruberian) is one of the bosses in Mega Man Zero 3. Tretista is a Mutos Reploid 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. These circuits act as the voices of compassion, aggression, and reason. When Dr. Weil brainwashed him to be one of the Weil Numbers, he could not think properly. Instead, his aggressive traits were amplified, furthering his beast-like nature, and he became violent and arrogant. When Zero went to investigate a giant elevator created by Neo Arcadia, he finds Kelverian protecting it, fighting him. Zero then discovers the elevator is used to transport mass amounts of E-Crystals to be used as energy. As with the other Judges, 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. Although not a weakness, Burst Shot is effective against him, as it can hit him multiple times.

Defeating him gives Zero the Absorber Body Chip and, if at A or S rank, the Gale Attack EX Skill.


  • Hell Bouncers - Tretista will detach his arms summoning two hounds that will try and jump at Zero.
  • Container Throw - Tretista will grab a giant box and tries to throw it at Zero, then dashes at it to destroy it. If Tretista manages to drop a crate on Zero at a corner, it is an instant kill regardless of Zero's vitality.
  • Steel Pipe Throw - Tretista will grab a metal pipe, bend it into the shape of a boomerang, and try to throw it at Zero. If shot with the Z-Buster while it is in mid-air, the pole will go back and hit Tretista instead.
  • Breath Gas - Tretista and his dog heads on his shoulders spit purple energy orbs that roll on the floor before disappearing.
  • Mega Stomping - Jumping attack.
  • EX Skill: Laser Claw (レーザークロウ) - Tretista Kelverian drops a large crate on the ground similar to his other box attack. If the player is fighting Tretista at A or S rank, he will summon a giant purple laser sword at the crate.


Mission: Search Facility
Zero's EX Skill: Gale Attack (Reppuugeki)

Stage enemies

Enemies in Tretista Kelverian's stage.


ゴルルルァ! Gorururua! The growling he does randomly throughout the battle
くらえいっ! Take this! Firing purple orbs
おりゃっ! Try this! Hurling a giant metal makeshift boomerang
ゴファー! Gofaa! Hurling a giant box
やっちまえ! Kill him! Sending his dogs to attack Zero
ガフッ! Gafu! The grunts his attack dogs make when hopping around
ひっさぁーつ! Special move!
("Hissaa!" in Mega Man Zero Official Complete Works)
Using his EX skill attack
ムフッ! Mufu! When hit with a stunning attack
なにぃ!? What!? When he is defeated



  • Tretesta (Tretista) comes from Italian tre (three) and testa (head); also, tritesta is Italian for three-headed, while Keruberian (Kelverian) is a play of Kerberos (ケルベロス Keruberosu; also known as Cerberus in English). Therefore, his name means "Three-Headed Kerberos".
    • In the English-localized Mega Man Zero 3 instruction manual, Tretista is better translitterated as "Tretesta Kerberion".
  • 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.
  • Tretista and Childre Inarabitta are the only members of Weil's Numbers that first appear to Zero already morphed in their "Punishment" forms. He only assumed his humanoid form briefly during the final stage, morphing afterwards.
  • Coincidentally, Tretista'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.
  • The boss Bifrost the Crocoroid from Mega Man ZX Advent has an appearance that is quite similar to that of Tretista. Both have similar standing animations, and both have an attack that sends a rolling weapon across the floor.
  • His three heads having a different thought system for judgement could be a reference to the three judges of Hades Rhadamanthys, Eacus, and Minos.
  • The Rockman Zero 3 commercial has Zero barely defeating Tretista Kelverian, although he is different in the commercial, lacking the heads on the shoulders, having three rotary cannons in place of his claws, and a slightly different torso.[1]
    • In addition, Tretista Kelverian falling down in a heap was reported to be Keiji Inafune's idea, as he insisted with the third trailer that "there needs to be something that falls down".


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