“Super-engineered squirrels, or something,” the Lackya were minions of the Gilded Duke before the Baron squashed him. Like the Jägermonsters, the Lackya must have a master, and signed on with Wulfenbach. Judging from the antagonistic one of them has with Minsk, they do not get along with the Jägers, and Minsk becomes very angry with Agatha when she points out the similarity in backgrounds.
The Lackya appear as fair-skinned (“Caucasian”) men with white or light grey/silver hair (with Sleipnir to them as "the footmen" and a Jäger general also calls them "feetsmen" once.), and color changing sclera in their eyes that shifts with their mood. Their typical uniform is a fuchsia coat with gold trim, a double-buttoned white waistcoat and black trousers.
They have been known to hiss when sufficiently aggravated. Since squirrels (whether super-engineered or otherwise) aren't known for hissing, this, along with their eyes, may indicate what "or something" might be.
While they look rather weak and have rather effete mannerisms, one is seenthrough the head of a warrior wasp, and they do seem to be quite willing to throw themselves into a good scrap.
Following Agatha's eventful stay on Castle Wulfenbach, it is noted that the Baron has dispersed the Jägers to distant points of the empire, leading to the Lackya being given more prominent responsibilities. It is also mentioned that when they become nervous, they tend to engage in a sort of hand-scrubbing gesture.