Arknights: Endfield Guide | How to Beat Triaggellos Boss

Here’s a guide on how to beat Triaggellos in Arknights: Endfield.

Game Guide by Ragib Rawnak on Feb 21, 2026

To win the fight against Triaggellos in Arknights: Endfield, you have to learn how its three parts work. The boss changes colors from red to green and then purple.

Each color has its own moves. If you wait for the right time to hit it and save your skills for when it is stunned, the fight goes much faster.

Arknights: Endfield, Guide, How to Beat Triaggellos Boss

Phase 1: The Red Phase

The boss starts out red. First, it will drop Glowing Rocks on you. You can just walk or dodge away to stay safe. Soon, a red circle will appear around Triaggellos.

This means it is about to use a heavy attack. You can stop this attack by using your skills with 1, 2, 3, or 4. You can also use Character Assist by pressing E. It is better to hit back than to just dodge because you deal damage while stopping the boss in Arknights: Endfield.

Watch for the boss to glow red, which means a Slamdown Attack is coming. When the boss gets stunned, use your Ultimate Abilities, Character Assists, and Signature Abilities all at once to take away its health.

Arknights: Endfield, Guide, How to Beat Triaggellos Boss

Phase 2: The Green Phase

The green phase is different because you cannot hurt Triaggellos right away. It starts with the Anchor Shockwave Ability. You need to stand near Originium Saplings so the wave doesn't hurt you.

Then, small enemies will show up. You have to kill them first. While you fight them, the boss will shoot Spikes into the ground in Arknights: Endfield.

Move out of the marked spots and lead the small enemies to you so you can kill them safely. After they are gone, the boss throws more rocks. These rocks make Shockwaves that you have to jump over.

Once these moves finish, you can hit the boss again. It doesn't use heavy circle attacks here, so use all your skills. If the fight takes too long, it will do another wave and start the green moves over.

Arknights: Endfield, Guide, How to Beat Triaggellos Boss

Phase 3: The Purple Phase

The purple phase is the last one and is usually the easiest. Triaggellos will turn invisible or have a purple glow. You can still hit it even if it is hard to see. It will shoot Missiles that make red marks on the floor. It also has a Missile Barrage that covers more space. Just keep an eye on the ground to see where to move.

Hitting the boss makes it stop being invisible. Watch for a red line on the dirt, which is the Laser Beam Attack in Arknights: Endfield.

Run to the side or get behind the boss. Once it starts the laser, it cannot turn around. It also shoots Red Balls, so stay behind it. When it gets stunned, finish the fight with everything you have.

Also, check our Arknights: Endfield Review and other guides below: