Board Thread:Questions and Answers/@comment-28320970-20160427172450/@comment-26044227-20160427174318

Set them as leader, and grind Maps 1 and 2 as needed. Note that if you're just looking to clear Map 2 to get to Maps 3 and 4, the night battles aren't particularly hard; I brought a team with 4 Tachis, 1 Tantou, and 1 Wakizashi in the mid-high 70s and didn't have any problems.