Clan Krik was a clan that was only featured in the 7th edition of the Skaven army book. Though their intent is unknown, it seems that they may be potential Clan Eshin allies; "Krik" sounds a bit like "crick", as in crick in the back, so they could've been decent backstabbers. However, this is mere speculation.
Warlord Skrich- the (probable) last Warlord for Clan Krik, Skrich was given the dubious honor of serving alongside Grey Seer Thanquol in an assault on Citadelle La Boeuf. Thanks due to Thanquol's concerning habit of changing plans at the last minute, the drawbridge leading to the citadel- which was supposed to be opened wide for Clan Krik -was still closed. It shouldn't be much of a stretch of the imagination to think that the Warlord didn't make it.