Two of the coolest monsters adventurers are likely to meet underground are the warrener — built from D&D’s umber hulk — and the xorn. Both are weird looking, not necessarily a threat unless you end up annoying them (intentionally or otherwise), and far more sapient than their appearance suggests.
The umber hulk was considered product identity in the original days of the Open Game license (as with the displacer beast). But with the movement of the Dungeons & Dragons SRD into Creative Commons, there are no prohibitions on a game built around the chassis of D&D (as CORE20 proudly is) from getting their umber hulk on. That said, that name always seemed a little meh to me, so “warrener” takes its place — from the way the relentless digging of these creatures creates warrens that wary underground adventurers learn to watch for and avoid.
One big update made to the warrener involves replacing the umber hulk’s confusion gaze with a slowing gaze. It was CORE20 developer Aaron Gray who pointed out to me that confusion effect of the umber hulk feels strange as an evolutionary defensive or offensive strategy, given that a creature under its effect is just as likely to attack the umber hulk as to flee them or stand fast. By slowing other creatures, the warrener is in a better position to catch up to prey, or to evade threats or creatures they just want to ignore.
(Click on the stat block header below to download the full stat blocks in PDF.)
