The "mercenary" category has a surprisingly big enough variety of different possibilities.
A lot of people look down on mercenaries because they most of the times lack a backer, but at the same time all of the bigger forces "need" them, because of the righteous faction's treaties which requires justification for a battle in the open, most of the times conflicts between sects are solved with short timed skirmishes which are consciously ignored by the other righteous faction forces.
So, that's when "mysterious" enemies with no affiliation come in handy, mercenaries are used to do the dirty work of those from high moral standing most of the time.
