Where do Hell Guards fall? While searching some Buddhist inspired pictures of Naraka I often found hell guards torturing others... Question is where are they on the rebirth cycle. Are they ausras? And if they  are created to hurt people how can they ever find a good rebirth.
Yes, they are Asuras. They are not created. They are also hell beings who become stronger from time to time due to their past good Karma and assume a position of command. At other times, they suffer like the rest.

They are not hurting people(humans). They are hurting beings who are at the bottom of the scale of virtue. So the Karma they get is comparatively less. In any case, they don't get any opportunity to do good. So, unless a past good Karma resurfaces, they have to wait till the end of the world to escape from hells.