While Lucifer was busy scamming a certain goddess out of far too many golden apples, his great-grandson, Arthur, was in the middle of robbing a Planet Lord of his treasures.
Looks like it ran in the family.
As for how they ended up here, it was quite a series of circumstances.
After Lucifer had left for Muspelheim, Arthur and Nicole had navigated their spaceship to the nearest inhabitable star system, deciding to touch down there for some rest after their week-long journey to Kriwon.
They also needed a change of scenery, as the constant sight of stars and the beauty of space had long since lost its novelty.
When they descended onto a deserted area, Arthur detected a strong source of energy in some nearby ruins, and, curious, he decided to check it out.
In the ruins, Arthur and Nicole stumbled upon the hideout of a band of thieves, who, unbeknownst to them, were quite notorious on this planet, whose name they didn't know.
