Making friends certainly has its benefits. When you become friends with another player, you can hire their Mercenary to join your party in quests and take advantage of the Mercenary's Leader Skill in addition to your own. Hiring a friend's Mercenary is also cheaper than hiring a stranger's Mercenary.
How to Add Friends
1. Tap on Friends on your lobby screen
2. Tap on Search Friend
3. Enter their Player Name or Friend ID to search.
How to Assign Your Own Mercenary
You can also set your own Mercenary to let your friends benefit from your unit's leader skill.
1. Go to Menu (top-left button)
2. Tap on Player Info
3. Tap on Assign
4. Choose the unit you wish to assign