After the Company of Heroes divulges the way to enter Titan's sanctuary, you must go there and defeat the primal.
How to Unlock
The Navel trial is unlocked by the level 34 Main Scenario Quest Lord of Crags.
The tank should turn Titan to face away from the rest of the party so they will not be hit by Rock Buster, a cone attack. Titan will also periodically use Tumult, which damages all players.
After taking a certain amount of damage, Titan will jump upward, and the outer ring of the area will be marked with a red ring. Stand as close to this ring as you can without standing on it. Titan will use Geocrush when he lands, and the closer you are to the center when this attack hits, the more damage you will take. If you are standing on the red ring, you will fall into the lava along with the outer ring of the arena and die.
At this point, Titan will sometimes target a random player with Landslide, a fire line attack. If the player does not step off of the fiery line before the cast bar completes, the player will be knocked back by almost half of the length of the platform. If the player is not near the center of the platform, they will be knocked off of the platform and die. Try to step off of the fire if you are targeted with this, or you can try staying near the center, or use knockback prevention moves such as Arm's Length or Surecast.
Later, Titan will do another Geocrush, further shrinking the battle area. This is the last time that he will use Geocrush during the fight.
Eventually, Titan will jump upward and will land in the center. After this, Titan's Heart will appear on his chest. Focus all attacks on Titan's Heart.
Titan will sometimes trap a random player in a Granite Gaol. Focus all attacks on the Granite Gaol until the player is freed. If you do not destroy the Gaol in time, the Gaol will implode and disappear, and the formerly trapped player will be hit by Granite Sepulchre and take a significant amount of damage.
Titan will target random players with a circle attack called Weight of the Land. Step out of the swirling circle to avoid this.
After you destroy Titan's Heart, he will jump upward and land, and then he will become temporarily invulnerable and begin casting his ultimate attack, Earthen Fury. The healer can prepare for this before the cast goes off by using their abilities to shield players, apply healing over time to players, and so on. After Earthen Fury hits, the healer should heal the damage to the party.
Completing the Quest
Defeating Titan will complete one of the quest objectives for the Main Scenario Quest Lord of Crags.