Joseph Silo was made into Darkness shortly after he arrived at Happy Miracle.
It seems he remained unaware of this for sometime while in the Inner Depths.
Now it seems you have stumbled into the territory of RAID.
Fear not, I, CTGPlayz, will guide a simple soul like you through.
After all, I did make this game.
Darkness will spawn in one of four corners.
Shine your flashlight on him to dissipate him.