Session Attacks (also known as Sessions) are the core battle mechanic in Tokyo Mirage Sessions ♯FE.
Session Attacks are special attack chains that are triggered by taking advantage of an enemy's weakness. If a character strikes the enemy with an attack the enemy is weak against, the other party members can immediately follow-up with attacks of their own. Strengths and weaknesses are based on a combination of Fire Emblem's standard weapon types (Sword, Axe, Lance, Bow) and the elemental categories of Shin Megami Tensei (Fire, Ice, Electric, Wind, Expel, Death).
Sessions can combo, and the higher the number, the more colorful the flavor text: i.e. a combo of two is
COOL, and upwards of fifteen is
Different Session skills are obtained by completing side stories and increasing a character's Stage Rank.