When Vexthra knocked Kent out, the tower used the moment to activate the three memory keys he had for the Faceless Assassin.
In those three parts of his past life memories, he experienced the planning and plotting moments that Faceless had to go through to kill a demon lord.
He experienced from the true expert the art of assassination. It was one of the intense moments and the experience that shaped Faceless Life. That finally awakened his nature as an assassin.
But it wasn't just about witnessing how Faceless killed the demon lord; he got to relive the moment Faceless formed the Midnight Shadows.
It turned out the Midnight Shadows weren't a fan group, as Kent had believed at first. In the memories he had recovered, when Faceless became an immortal, he realized the universe is big.
He alone wasn't enough to handle the many threats there were, so he formed the Midnight Shadows, where he personally trained assassins from scratch.
