Temporary companions

Contrast:
* Companion - a permanent companion
* Group
* One of many

These never join your quest of whatever, they might acknowledge it, but they think they have other things to do that are equally or more important, or you never divulge your quest to them.

You might be travelling into some place and someone, possibly you, suggest to another who is planning on the same trek that travelling together increases both of your survival chances, but once you reach your destination, you go on your separate ways. It might be that you acknowledge the dangers ahead or know nothing about them and hire or convince someone to help you through, but once that's done, the guide goes back to doing whatever they were doing.

There's other potential cases, but the travelling companion through monster/bandit infested region is a common one.