Persona 5 Tactica

This is an achievement tied to the main story, and the description explains enough what you'll have to do to unlock it. You'll need to rescue all your Phantom Thief companions (Futaba, Ann, Ryuji, Haru, Yusuke, and Makoto) that are seized by the power of Lady Marie's love spell, where they now follow her orders to take you out. This happens after completing your first mission where you're introduced to the tactical turn-based combat mechanics to the game. From here on out you'll need to progress and complete missions using Joker, Morgana, and Erina to free the other Phantom Thieves (who'll join your party as playable) as you play through. The process for your teammates that will rejoin you goes as follows:

Ann, Futaba - Complete Mission 8 (Signal the Counterattack) - Defeat Ann

Ryuji, Haru - Complete Mission 11 (Beauty and Brawn) - Destroy Marie's Flag

Yusuke, Makoto - Complete Mission 14 (A Bitter Retreat) - Reach the target (area highlighted by a blue lighted border at the other end of the play field) with entire party.

Proceed with the story after completing Mission 14 where you get the cutscene with Yusuke and Makoto's return to the LeBlanc hideout and officially join your party. The achievement will pop-up on screen afterwards.