Colt Canyon

When you rescue a survivor, you will almost always have the choice to have them join you as a companion. You need to do this 5 times (meaning the earliest you can get this is stage 2-2).

Having 5 companions alive is not super useful or easy, so I would do a run just aiming for this achievement.

You can heal your companions by walking up to them and hitting - .5 of your current health will become 1.0 of theirs. You can also tell them to move to your cursor with to get them out of danger.