The Lost Princes (DCC)

Groundlings originally appeared in one of the 2nd edition Forgotten Realms monster books, not sure which one. I first encountered them in the 3.0 Monsters of Faerun. They are monstrous humanoids created by Zhent magic-users. They were created by mixing dwarven stock with giant badgers. This is cool and all, but I want to expand it and take them out of the Realms.

Baldr-Vil (or more commonly Groundlings)

Nearly three centuries ago the greedy wizard Zhen-tar sought to take the riches of the dwarven kingdom of Kalduran. To aid him in his task he needed the perfect assassins. He wanted a strong breeding stock and found it when he encountered the kingdom's young princes, training with the king's guard in the nearby forest.  The evil magic-user used his abilities to subdue the warriors and ferry them to his laboratory. There they were subjected to tortures to break their wills and magic to warp them into the first Baldr-Vil (Dwarven for "lost princes"). The victim of their first assassination was the king himself. During the funeral Zhen-tar appeared before the crowd of mourning citizens and revealed the true nature of the king's assassins. This would prove to be his undoing, as the Hells know no fury like a grieving dwarven mother and widow.

The queen rallied her people and a nearby clan of gully dwarves. The combined dwarven army scoured the land and eventually found Zhen-tars hidden lair. Their master slain the surviving baldr-vil (as the dwarves named them) fled. The queen could not bring herself to have the creatures hunted.

Baldr-vil can breed with dwarves and the offspring have a 90% to be born baldr-vil. The original "clan" were all male, though females have been born since Baldr-vil tend to avoid dwarves. However, their voracious appetite for flesh often brings them into conflict with the halfings, elves, and humans (who call them groundlings).

Baldr-vil: Init +1, Atk bite +4 melee (1d8) or 2 claws (1d4/1d4); AC 16; HD 3d6; hp 15; MV 30'; Act 1d20; SP burrow, drag, dwarf blood; SV Fort +4, Ref +2, Will -1; AL C

Baldr-vil can burrow through the ground effectively gaining a swim speed equal to their movement through dirt and most stone. Their prefered tactic is to use this abilitly to sneak up on opponents and burst forth from the earth, making surprise attacks.

If a baldr-vil can hit an  medium or smaller opponent with both claws attacks it can drag the victim into the ground at the end of the round. Creatures pulled into these tunnels can only attack with small or natural weapons (at a -2 penalty). The baldr-vil receives +2 to hit the target. On his turn a victim may take an action to make a strength skill check (DC 20) to climb out of the tunnel.

Despite their magically warped nature, baldr-vil are still dwarves.