20ef1efc_Spiderkind_Chapter____D_D_Wiki__Benefit
[Feat] Eyes of the Abyss [Prerequisites] Demonic Ancestry [Benefit] 
Your eyes glow with an inner fire of some unusual color. The glow increases your perception and allows you to see in the dark.
Feats (Arachonomicon; the Book of Spiderkind Chapter) - D&D Wiki
Benefit