Clan Skrittlespike
Fear of the sun- heliophobia, in other words -is somewhat natural in Skaven society. Despite this, Clan Skrittlespike seems to have taken this fear to an unnecessary extreme. Lingering in the darkest depths of Skavenblight, these rats have developed a pair of concerning mutations- overgrown irises (obviously light-sensitive, but ideal for night missions) and enhanced hearing (which may be more of a curse, as most noises tend to scare these Skaven). While this does limit the clan's capabilities to a certain extent, it also gives them a few special gifts.