Colossus (HEL-A27)

The Colossus is a giant mechanized robot designated HEL-A27 that appears in BO7 Endgame as part of the “Colossus of Avalon” World Event. It is a variant of the Riese-model Giant Robot that has appeared across multiple Call of Duty Zombies maps. In Endgame, it functions as a large-scale environmental encounter requiring coordinated squad effort to complete.

What the Colossus is

The HEL-A27 is a giant robot of uncertain origin within Endgame’s fiction. Whether it is genuinely present on Avalon or hallucinated by Specter One operatives due to Cradle toxin exposure is left ambiguous in the game’s lore. Its official in-game designation in the “Colossus of Avalon” World Event is HEL-A27.

The Colossus patrols a fixed area within Zone II of Avalon during the World Event.

World Event: Colossus of Avalon

The Colossus of Avalon is a World Event that takes place once per match in Zone II of Avalon. World Events are large-scale encounters recommended for multiple players.

Once the event becomes active, HEL-A27 engages and the fight begins. If the Reactor Core is not destroyed before the event timer expires, HEL-A27 flies away and the event fails.

Entry methods

Players must enter HEL-A27 to damage the Reactor Core inside. There are two ways to get inside the robot.

Foot portal (ground entry)

Shoot at the underside of HEL-A27’s foot until a portal opens. The portal is accessible from ground level and does not require any ability. This is the most accessible entry method and does not depend on having a specific loadout.

Note: Timing matters. HEL-A27 is moving, so the foot portal will close or move as the robot steps. Wait for the robot to pause or step down before targeting the underside of the foot.

Back portal (elevated entry)

A second portal is located at the top of HEL-A27’s back. Reaching it requires either the Grappling Hook Minor Ability or a Redeploy Drone to reach the necessary height.

The back portal provides a faster entry route for players who are already at elevation or have movement abilities available.

Fight phases

Once inside the Reactor Chamber, the fight proceeds in three phases corresponding to three circular plates on the chamber floor.

1. First plate (ground floor): Activate the circular plate on the ground level. This reveals corresponding red lights around the Reactor Core. Shoot all red lights to lower the Reactor Core’s protective shield. Deal damage to the Reactor Core until the shield regenerates.

2. Second plate (second floor): Repeat the process with the circular plate on the second level of the chamber. Activate the plate, shoot the red lights, and damage the exposed Reactor Core.

3. Third plate (third floor): Repeat the process a final time with the plate on the third floor. Destroying the Reactor Core after this phase disables HEL-A27.

The protective shield returns after each damage window, requiring players to repeat the plate activation and red light shooting sequence for each floor.

Community notes on hitboxes

Caution

Players report that HEL-A27’s hitboxes are unreliable. Shots which visually connect with the Reactor Core and red lights do not always register as hits. Players report that repositioning slightly and maintaining consistent angles on the red lights improves hit registration. This is a known issue as of the time of writing.

Exfil via head

When the Reactor Core is destroyed, players have two exit options:

• Return to Avalon: Use the main portal inside the chamber to exit HEL-A27 and continue the match
• Exfil: Use a separate portal to enter HEL-A27’s head. The head then detaches and flies the player out of the match, counting as a successful exfil

The exfil-via-head option ends the match for those players regardless of the remaining match timer. Players who choose to return to Avalon can continue completing objectives and use other exfil methods.

With the Reactor Core destroyed, HEL-A27 shuts down and remains inactive for the rest of the match, regardless of whether its head is still attached.

Related pages

World Events All World Event encounters and how they work.

Map Traversal Grappling Hook or Redeploy Drone for the Colossus back entrance.

Exotic Skills World Events reward Exotic Skills on completion.

Exfil Completing the Colossus allows exfil through the robot's head.

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Data sourced from community research and in-game documentation. Information may change with game updates.