At the moment it's the first companion you hired/the one who's been in your party the longest. It'd be better if it was the first companion on the party list.
Also I couldn't find a way to increase companion relations, an option to give them gifts or some other way to increase relations with them would be great.
Also I couldn't find a way to increase companion relations, an option to give them gifts or some other way to increase relations with them would be great.