Inktober Monstrosities: X for Xill

The xill are a race of cruel and strange, four armed, flame red alien creatures, native to the Ethereal Plane, that travel to the Material Plane to hunt for potential hosts for their eggs, usually in the form of adventurers. Sometimes they also hire out their expertise as mercenaries and men-at-arms, probably requiring double pay due to their extra set of arms.

In D&D the xill first appeared in the Fiend Folio for first edition AD&D and then in the Monstrous compendium, Fiend Folio appendix, for second edition. In third edition they got prime billing, appearing in the original Monster Manual.