# Triaggelos Boss Fight Guide > Defeat Triaggelos by learning the attack tells for all three phases and saving burst damage for stun windows. This is for players who want a clear phase-by-phase plan for clearing the fight more consistently. - **Game:** Arknights: Endfield - **Category:** Getting Started - **Author:** LongBeam (https://guides-factory.com/about) - **Difficulty:** Beginner - **Reading time:** 8 min - **Published:** 2026-08-16 - **Updated:** 2026-08-26 - **Tags:** Arknights Endfield, boss fight, combat mechanics, phase guide - **Adapted from:** [How to Beat Triaggellos Boss Fight | Step-By-Step Guide ► Arknights Endfield](https://www.youtube.com/watch?v=nQFRlq__3t4) - **Canonical URL:** https://guides-factory.com/guides/triaggelos-boss-fight-guide --- Defeat Triaggelos by learning each phase's attack patterns, saving your strongest abilities for stun windows, and handling adds efficiently. You'll recognize when to interrupt, dodge, and burst, making the fight much more manageable. Phase transitions and visibility challenges are key, and the fight rewards careful resource use. ## Quick answer | What | Answer | | --- | --- | | Phases | 2 phases | | Best damage window | When the boss is stunned | | Phase 2 damage rule | Attack after the adds are defeated | | Phase 3 visibility | Invisible, sometimes with a purple aura | | Phase 1 interrupt | Use 1, 2, 3, 4 or E to cancel heavy attacks |

Patch may have changed this This guide describes three distinct phases (red, green, purple), but some game versions list only two. Check the in-game UI for current phase structure.

## Learn the three phases Triaggelos cycles through distinct combat phases, each defined by a color and unique mechanics. The boss opens with the red phase, focusing on ranged and heavy attacks that must be interrupted. The green phase introduces arena-wide hazards and a wave of smaller enemies. The final phase, purple, is marked by the boss becoming invisible or partially visible, with new attack patterns built around tracking and positioning. ![Boss Triaggelos with red glowing core and health bar, three player characters in combat, Cradle of the Ages mission objectives at left.](https://api.guides-factory.com/media/uploads/2026/08/01-phase-one.jpg "Triaggelos begins the fight in the red-colored phase one, confirming the start of phase one.") - Phase 1 (red): Focuses on interrupting heavy attacks and careful dodging. - Phase 2 (green): Begins with shockwave arena attacks and requires defeating spawned adds before the boss becomes vulnerable. - Phase 3 (purple): The boss turns invisible, sometimes only highlighted by a purple aura. Tracking and hitting is possible even during full invisibility. You will learn the attack tells and counter strategies for each phase as the fight progresses. ## Handle the red phase The opening phase tests your ability to interrupt and dodge efficiently. Follow these steps to survive:

Watch for glowing rocks Easy to dodge by running or using the dodge move. 0:01 ↗
Interrupt heavy attacks when the red circle appears Use abilities tied to 1, 2, 3, 4 or your E assist skill for interruption. 0:31 ↗
Save abilities for frequent heavy attacks Patience is rewarded in this phase; heavy attacks happen often.
Dodge the slam attack The boss glows red before a heavy slam — run or dodge to avoid.

![Boss Triaggelos with a glowing red targeting circle around it, indicating a heavy attack in Arknights: Endfield. Player abilities 1, 2, 3, and 4 are visible at the bottom right. Several fiery rocks are scattered across the battlefield.](https://api.guides-factory.com/media/uploads/2026/08/02-heavy-attack.jpg "The boss displays a red circle, signaling a heavy attack during phase 1.") ## Save burst damage for stuns Stun windows are the best opportunity to inflict heavy damage. The boss is vulnerable and will lose health rapidly during this period. Focus your ultimates, assist skills, and signature abilities on these moments for maximum effect. This principle applies in every phase: avoid burning key damage abilities outside stun windows unless survival demands it. ![Combat screen showing the boss Triaggelo in the center surrounded by visual effects; the action log displays 'Lifted' and damage numbers, with burst skills available but no clear stunned indicator.](https://api.guides-factory.com/media/uploads/2026/08/03-stun-window.jpg "Combat is intense and burst abilities are being used, but it is not unambiguously a stun window for maximum damage.") - When Triaggelos is stunned 1:29 ↗, unload your highest-damage skills. - Holding back until these windows ensures you can clear phases much faster and reduce overall risk. ## Clear the green phase safely Phase two introduces both arena hazards and adds. Strategy and timing are vital here:

Anchor shockwave attack Start phase two by using originium saplings as cover to avoid shockwaves. 1:29 ↗
Defeat the spawned adds Boss will spawn smaller enemy types; defeat these before the boss becomes vulnerable. 1:59 ↗
Dodge spikes Move away from the areas marked by incoming spikes.
Jump shock waves from rocks Later in the phase, rocks cause shockwaves — jump over them to avoid damage.
No critical-hit attacks in this phase After clearing enemies, you can use all abilities freely as the boss does not use critical attacks. 2:29 ↗
Repeat the cycle Phase repeats attacks and hazards until the boss is stunned and the fight advances. 2:58 ↗

![Battle screen showing the Triaggelos boss, multiple smaller enemies, and originium saplings providing protection during an arena attack in the green phase.](https://api.guides-factory.com/media/uploads/2026/08/04-phase-two.jpg "Phase 2 begins with the boss, adds, and protective points visible on the battlefield.") ## Track the invisible purple phase The final phase challenges your ability to keep up with attacks while tracking the boss's position. Follow these steps:

Watch for invisibility and purple aura The boss may be entirely invisible or highlighted only by a purple aura. 3:28 ↗
Hit the boss even while invisible Damage removes invisibility and makes the boss easier to track.
Dodge missile attacks marked by red circles Missiles are telegraphed by ground markers, so move out of their range quickly.
Avoid the laser beam marked by a red line The direction is fixed once fired. Run to the side or get behind the boss after the attack. 4:20 ↗
Deal heavy damage after stun Unload burst skills once the boss is stunned to finish the fight.

![Boss Triaggelos in phase three with a visible purple aura at the center of the arena. The player characters are approaching, and the boss health bar is full.](https://api.guides-factory.com/media/uploads/2026/08/05-phase-three.jpg "The purple aura signaling phase three and partial invisibility of Triaggelos is visible, illustrating the challenge of tracking the boss during this stage.") ![Arena view with a boss marked as Triaggelos, a straight red line showing the direction of the laser beam attack, multiple characters present, and ground markers for other attacks.](https://api.guides-factory.com/media/uploads/2026/08/06-laser-attack.jpg "The beam is easy to avoid once the line appears.")

Tip Stay close and move behind the boss after its attacks for easier targeting. Watch for ground markers and attack tells to minimize damage taken.

## Also worth knowing

Before you commit - **Use a scan ability in phase three.** A scan effect reveals Triaggelos clearly while it is invisible and can interrupt its cloak. - **Expect poor visibility on mobile.** On low graphics settings, the purple aura is difficult to spot, making phase three much harder. - **Overlevel the fight if the mechanics keep beating you.** A strong team at level 60 can steamroll it, even if mechanics are not executed perfectly. - **Treat the trimmed medal as a separate goal.** Earning the trimmed medal for this fight is much more punishing than completing the basic clear.

--- ## FAQ ### How do you stop Triaggelos' heavy attacks? Use character abilities on the number keys or a character assist with E to interrupt the attack. Dodging also works, but interrupting is better because it stops the move and still lets you deal damage. Save those tools for the heavy attacks because they happen often in the first phase. ### When can you damage Triaggelos in phase 2? You need to clear the smaller enemies first. After that, the boss becomes vulnerable and you can attack freely until the next shock wave sequence starts. This phase also has no critical-hit attacks, so it is a good time to spend your stronger abilities. ### Can you hit Triaggelos while it is invisible in phase 3? Yes, you can still hit it even when it is invisible. A purple aura may appear around it, and damage will also remove the invisibility, making it easier to track. A scan effect from comments can also help reveal it more clearly. ### What is the easiest way to beat the boss overall? Learn the phase-specific tells, dodge the obvious area attacks, and spend your strongest damage when the boss is stunned. The fight is much easier if you do not waste burst abilities before a stun window. Phase 3 is usually the least dangerous once you stay behind the boss after its attacks.