The story of my last turn: Wanted Chrom & Sumia to weaken an enemy. Sumia should attack twice leaving enemy with a little health left, and take some damage herself. She attacks and hits. Chrom joins in with an assist (40% chance). Chrom shields Sumia from the enemy attack (10% chance). Sumia attacks again and knocks enemy out with a critical hit (3%). True story. I would upload a video if I could!