One notable twoll is Bogroll.
Apparently personal hygiene is a weak point of twolls.Erf-b1-p037
It is not clear whether regeneration is a special ability shared by all twolls or it belongs to Bogroll only.Erf-b1-p040a 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 Bogroll's bodyErf-b1-p132, 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. If this is true, Bogroll would be gone permanently.