254 is a Vassal, a vat-bred homunculus from the Walfismeer, currently residing in Flotsam. Most Vassals are slaves to crazed, fleshwarping wizards, but 254 happens to be employed by Geverspike (even if he still acts like a slave; it is apparently the way of his people).

The Shields of the Sorrowfell hired Geverspike and 254 as companions in Flotsam, and they accompanied the Shields to the Sea of Howling Souls and Frost Spire.

Image retrieved from http://www.giantbomb.com/roger/3005-24852/ on September 18, 2016.