Morale is an issue that affects any group of people working together, and it's significant in this game. The level of morale of each merc isn’t about having a bunch of whiners or cheerful soldiers; it directly affects their performance on the battlefield.
Morale can range from very low to low, normal, good, and very good. A normal morale level has no impact on the merc, and each level gives a 10 percent bonus or penalty. It may not seem like a large amount on a first glance but having a 20 percent penalty really changes the performance of that merc.
To build a good team, you need to check their traits and try to make them as happy as possible. It’s impossible to please everyone, but it is something to consider when hiring new mercs and if you need to split up a squad.
Relationships
Mercs are “real people,” with their own likes and dislikes. It takes a special type of person to become a hired gun, and you have to expect some conflicts. In fact, many of the mercs won’t join you until you have proven yourself or hired someone they like.
Putting people together who are not on good terms is never a good idea if you can avoid it. An unhappy team member brings down morale and reduces effectiveness in combat. The merc section contains a complete list of positive and negative parings.