SCARLET NEXUS

This achievement requires that you get through all Bond Episodes on both characters for Arashi. Bond Episodes are unlocked via story progression and are available in certain Standby phases.

You don't need the character to be in your platoon when initiating the Bond episode, if the character isn't part of your platoon you can initiate the bond episode by sending them a text via the in-game chat system. If they are already part of your platoon you can find them goofing around in the hideout.

Yuito
Episode 1 – Standby Phase 2
Episode 2 – Standby Phase 6
Episode 3 – Standby Phase 7
Episode 4 – Standby Phase 10

Kasane
Episode 1 – Standby Phase 4
Episode 2 – Standby Phase 6
Episode 3 – Standby Phase 8
Episode 4 – Standby Phase 10
Episode 5 – Standby Phase 11

EDIT:
All of these MUST be earned by starting your next character on Ex New Game (Thx Fat Grover)

You CAN also get these after you beat the game. (Thx PhotoSage)