Arik has been traveling for... several years. He kind of isn't keeping count. Sometimes he spends a while not traveling; you rescue someone's beautiful daughter or handsome son from some kind of troll, and they insist that you stay with them a while and rest your weary heels. That usually lasts until they find him in bed with their beautiful progeny, at which point he takes his escape bag and makes for the road. But sometimes it lasts a few months. (There have been cases where it's lasted almost nine.) But he travels, and he travels in a generally westerly sort of direction. And he kills monsters along the way, because he's got a sword and some spells and that's often all it takes.
The villagers of wherever the hell this is have a problem. They have relayed to Arik that their graveyard has been losing corpses, at a rather alarming rate. (In Arik's opinion this is better than gaining them, but not by very much.) There are signs that the corpses have been vanishing into a nearby cave. In that cave is said to be a demon, but the demon has not done very much of note up until recently.
Arik does not care to give it the opportunity to do anything of more note, so he saddles up Tommy, his pecopeco, and rides him to the mouth of the cave. Hopefully there will be a rock suited to acting as a hitching post. It's not that Tommy will wander off, but given free rein he might camouflage himself under a bush so as to bite Ari's shins when he emerges, and no one needs that kind of stress.