Need help finding a Guide verse manhwa.

Bl, both characters have dark hair, there were twin guides as well, last chapter I read was the building getting covered in monsters.
Plot: the very first scene In prologue is the guide going to give the esper I think a guiding. The plot is espers/fighters have a watch that says how corrupted they are, higher they go the worse they are. This guy who was rlly high up in the 80% doesn’t have a guide bec of trust issues so he gets help from the regular guides, I remember there being twins that helped him. After a rlly powerful guide is discovered from a test, he gets relocated to become a guide for this esper, first time they meet he faints and I remember the esper taking a nap w him and feeling better. It’s an ongoing manhwa and the last scene was the building getting absolutely covered in the monsters creating something like a “cube” and they were abt to fight it.also the twin brother was in danger bec of the cube