Tethys the Defended is one of the secret bosses tied to Destiny 2’s Monument of Triumph activities. While finding him can be more challenging than defeating him, knowing the correct path makes the encounter straightforward.
| Detail | Information |
|---|---|
| Boss | Tethys the Defended |
| Destination | Dreaming City |
| Region | Rheasilvia |
| Starting Point | Divalian Mists |
| Identifying Feature | Smoky aura around the boss |
| Special Mechanic | Shield vulnerable to Telesto |
| Recommended Difficulty | Solo-friendly with proper loadout |
Location of Tethys the Defended in Destiny 2
Tethys the Defended can be found in Rheasilvia, the northern area connected to Divalian Mists in the Dreaming City.

After entering Rheasilvia from Divalian Mists, follow the path toward the large bridge. Before crossing it, take the left-hand route instead. Continue moving through the area until you reach a section featuring a blue mist-covered river.

As you travel along this path, watch the right side for several illuminated black plants growing near the terrain. These glowing plants serve as a useful landmark that confirms you’re heading in the right direction.

Keep moving forward while looking to your left. You will pass the first cave and eventually reach a second cave entrance tucked into the rock wall. Tethys the Defended spawns near this second cave.
How to identify Tethys the Defended boss
Unlike many standard enemies in the area, Tethys the Defended is easy to recognize once he appears. The boss is surrounded by a noticeable smoky aura that stands out against the environment.

If you reach the second cave and spot an enemy with a dark, smoky effect surrounding its body, you’ve found the correct target.
How to beat Tethys the Defended
Breaking the shield
The encounter’s primary mechanic revolves around Tethys’ powerful shield. Regular weapons will struggle to make meaningful progress against it.

Equip Telesto and fire directly at the shield. The explosive bolts will eventually disable the protective barrier, exposing the boss to normal damage.
Dealing damage
Once the shield drops, switch immediately to your strongest damage options. Heavy weapons, Supers, and burst-damage abilities can quickly reduce the boss’s health before the shield becomes a problem again.

Rocket Launchers, Grenade Launchers, Linear Fusion Rifles, and high-damage Supers are all effective choices.
Understanding the “Are You Sure About This” triumph
The Monument of Triumph challenge tied to this encounter is called “Are You Sure About This.”

The triumph description states that players must use the Exotic weapon Telesto to defeat Tethys the Defended, who was last seen in Rheasilvia within the Dreaming City.
This means simply finding and killing the boss is not enough. To receive triumph credit, Telesto must be used to secure the defeat.
Recommended loadout for Tethys the Defended
| Slot | Recommendation |
|---|---|
| Exotic Weapon | Telesto |
| Heavy Weapon | Rocket Launcher or Grenade Launcher |
| Energy Weapon | High-damage Legendary |
| Super | Any burst-damage Super |
| Armor Mods | Ammo Finder and Weapon Surge Mods |
Tethys the Defended is hidden near the second cave in Rheasilvia of Destiny 2. From Divalian Mists, head into Rheasilvia, take the left path before the bridge, follow the blue misty river area, and use the glowing black plants as a landmark. Once you locate the second cave, look for the enemy surrounded by a smoky aura. Break the shield with Telesto and finish the fight with your highest-damage weapons to secure the kill.