The Veil ability is on the bottom of the Thule Medallion HUD icon (corresponding to down on the D-Pad in the console versions) and allows the player to enter the Veil. This highlights most enemy types in bright green, and certain objects such as exploding barrels and important or vulnerable areas such as the weak points of the Heavy Trooper in bright red. Veil also highlights the stone covers which hide almost every Tome of Power in the game. BJ moves faster in the Veil and can jump further.
Veil also has one undocumented ability when using a grenade; while holding the grenade to cook it, a faint smoke-like trail will extend from the middle of the screen to show the trajectory the grenade will follow when thrown.
Veil does not actually count as a Veil Power like the other three; as a result BJ can gather energy from Veil Pools even with this ability active. The three other Powers will all automatically activate Veil and provide the same bonuses as the ability on its own. It drains roughly half as fast as any of the other powers.
Some object in game may or may not exist in the Veil. Using Veil you can disсover some secrets, such as a safe way around Slowing Crystal traps and unseen ladders. Doors and walls, marked by the sign of the Black Sun, do not exist in the Veil, and can be used to attack enemies from a safe place, remaining unseen. Furthermore, Geists can only be seen and interacted with while this power is active.
There are 4 upgrades tagged as "Veil" upgrades, though these are actually general upgrades for the Thule Medallion which enhance all of its powers. They are unlocked by collecting Tomes and are not bound to completing certain missions.
- Inner Light. Unlock: get 2 Tomes. Cost: $1,500. Increases the Veil Energy Pool by 50%.
- Veil Sight. Unlock: get 4 Tomes. Cost: $2,000. Allows BJ to see enemies through solid matter. This ability is rather hit-and-miss; it seems BJ must have seen the enemy already for it to function. It combines well with the upgrades to Empower.
- Inner Brilliance. Unlock: get 8 Tomes and have Inner Light. Cost: $1,500. Increases the Veil Energy Pool by another 50%, making it double the starting size.
- Crystal Harmony. Unlock: get 16 Tomes and have Inner Light and Inner Brilliance. Cost: $2,000. Increases the speed at which Veil Energy is regenerated over time when relying on the black-sun energy pool to recover. Also makes your energy recharge slowly even when there are no pools nearby.