In Indies' Lies, you can invite partners to build a stronger team.
After defeating a chapter boss and before entering the next chapter, you will see the 'Invite Partner' page where you can select 1 out of 3 partners to join your team.
Before selecting your partner, you can view partner details, such as their starting deck and growth potential (cards that might drop).
After choosing a partner, you can drag characters to change formation. A lot of enemies like to attack the front row so keep that in mind when you're changing formation.
During battle, check the ‘Change Formation’ box when restarting a battle to adjust character positions. When you're back on the map, you can click the team icon at any time to change formation.