Overview
Tenebrum is a boss encountered during the Gate to the Otherworld main quest in Chapter 4 of Crimson Desert. This fight takes place immediately after you insert the batteries and extract the unstable core. It is not a traditional combat encounter; instead, it plays more like a flying puzzle fight where you use Force Palm to strike Tenebrum in the air above the plaza.
Phase 1: Reveal the Weak Point
Before you can deal any real damage, you need to reveal Tenebrum's weak point. Hold L1 + R1 (LB + RB on Xbox), then press R1 / RB to target the flying specter. A square-shaped weak point appears on Tenebrum. You only need to do this once at the start of the fight.
Phase 2: Flight Combat
Take flight. Double-press Square (X on Xbox) to jump and activate your wings.
Position over the center. Fly above the center of the plaza where the floor is missing. Updrafts of wind will catapult you upward toward Tenebrum.
Strike with Force Palm. While airborne and near Tenebrum, press R3 / Right Stick to land Force Palm hits.
Time your attacks. The best window to deal damage is when Tenebrum hovers in the center and charges up an attack. He stays still during this windup, giving you several free hits.
Spirit Management
Force Palm attacks consume Spirit. After several consecutive strikes, your Spirit will run out and you will be unable to attack.
To recharge Spirit, hold L3 + R3 simultaneously.
While recharging, hide behind one of the pillars in the plaza to avoid Tenebrum's projectiles.
Resume attacking once your Spirit refills.
Avoiding Damage
Tenebrum fires projectiles that can knock you out of the air. Getting hit causes fall damage on top of the projectile damage.
Stay mobile during flight. Do not hover in one place for too long.
Heal using food items (D-Pad Right) whenever your health drops.
If you get knocked down, use the updraft in the center to get back into the air quickly.
Tips
This fight is more confusing than it is difficult. Once you understand the flight-and-strike rhythm, it goes smoothly.
You do not need to chase Tenebrum around. Let the wind currents bring you up and attack when he is stationary.
Keep an eye on your Spirit bar. Running out of Spirit mid-air with projectiles incoming is the most common way to get knocked down.
Stock up on food items before starting the Gate to the Otherworld quest chain. You will need them for healing between Force Palm volleys.