He was just out there, minding his own business, when he had first been summoned.
Big day for any imp. First summoning. Yep... time for a new 'master' to learn the ropes.
It would mean weeks (if not years) of service, slaving away, being beaten and abused while doing his new master's dirty work. It would be horrible. It would be agonizing. It would be unbearable. And in the end, it would be worth every moment of it. For, while he would be 'serving' his 'master', he would be slowly tainting them until they could be turned to the demon lords dark purposes.
And then.... then he had been banished, unexpectedly, in a battle and ended up............ here.
This was so not in his contract.