That was the name of an undead keep back in Aegis. Always occupied by them, and players could just rally up and do petty attacks whenever they wanted to.
Unk was the name of the first Undead Keep that appeared in Aegis just north of Snowy Fields and Alsion. They launched their attacks from there till we sieged it following the destruction of Snowy Fields. Then they just plopped their tower down in Snowy Fields.