Monstress is a villain in the Spawn series.
History
Monstress first appears in the Spawn #266 as the villain against Malcolm Dragon,Ant,and Spawn. She is some sort of super-villainess who commaneds a horde of demon like creatures which she uses to terroize the city and it was up to Spawn,Malcolm,and Ant to stop her.It was though as her and army manage to struggle against Spawn and his allies but eventually Spawn and his crew managed to beat her and her army. Apart from this she hasn't been seen since then.
For her powers and ablitlies,Monstress seems to have superhuman Strength,Speed,Stamina,and Durablity. She also has the abillity to command a demon like army at her disposal.