One notable twoll is Bogroll.
Apparently personal hygiene is a weak point of twolls.
It is not clear whether regeneration is a special ability shared by all twolls or it belongs to Bogroll only. It was not mentioned what powers regeneration gives, but it was speculated that Bogroll might restore himself back from the dead.
The Royal Crown Coalition burned his body, possibly to prevent regeneration from happening. This may indicate that all twolls regenerate, burning prevents this from occurring, and that these facts are common knowledge in Erfworld, making twolls very much like trolls in Dungeons and Dragons.