Fair enough, as am I.
So far, thinking the imp'll be named Nkiruka, a small creature who spends a fair amount of time in the ruins hiding and harassing would-be explorers and archaeologists. They (not sure on gender) spend some time in the city, of course, mostly playing with unattended children and pranking people. The problem is Nkiruka's sense of pain is different from most others and their sense of empathy all but nonexistent. As a result, Nkiruka lives in the ruins to avoid angry parents and workers.
When Nkiruka has to fight, I suppose they'd go for quick blows and move away, trying to lead an opponent into a trap of their own making.