"Cult of the Vault" is a challenge from Tiny Tina's Assault on Dragon Keep DLC
The First symbol is found at the far end of the Pit, near where you found Sir Boil during Loot Ninja. Head into the structure opposite the bridge and jump through one of the far windows. Look between the windows to find the Vault Symbol.
the Third Symbol is found in an elevator shaft. Fight your way on through the Nefarious Battlement. Clear the area so you can access the lower gate. Head on through to the elevator that is nearby and ride down in the elevator. Look up to find the final Cult of the Vault Symbol.
Ranks and Rewards
Badass Ranks: 5