Aurel the Fallen
Legendary Mage also in the gacha
He guarded the Sanctum until the Sanctum fell, then went on guarding the ruin out of habit. The light he calls is the same as before; it just no longer reaches a ceiling.
How to get
Defeat the Fallen Angel. Aurel wants to relieve the watch of someone who does not know he died.
Unlocks at: Fallen Sanctum
The gacha hands this companion over sooner — the free path still stands, and it is the same for everyone.