Can always just play a Tiefling as you would a mercenary now you have a mercenary Tiefling that cares only for gold. Sure it's not demonic instead devilish but thats just schematics. The heart of 5e is your not bound to an alignment. Your choices create that, same with in game. You care nothing for gold, then choose dailogue options that reflect that. Ask for compensation as your doing things. If they don't cough it up, steal their shit!
yeah demonic tieflings would be pretty cool looking if down right, but as is often said. Foul bloods all look the same, and smell the same.
