Umbra

Umbra is the greater deity of assassins, masks and murder.
Umbra is the twin brother of Sheoth, the Lord of Laughter. Some heretics go so far as to claim that the two gods are in fact two faces of the same entity, so great is the split in the deity's self-perception. The truth is unknown, but these rumours have spread far enough that the followers of Sheoth are always beheld with a degree of wariness and even a tinge of true fear.