In Metaphor: ReFantazio, aside from the protagonist, you'll have the opportunity to recruit seven additional party members to join you on your journey and participate in combat. Gallica is present from the start but won't engage in battles as effectively as the others. Each member joins at specific times tied to story events, and knowing these can help you prepare for their arrival. Be warned, though: this information includes slight spoilers about who joins your party.
Each Party Member & What Day They Join In Metaphor: ReFantazio
Every party member in Metaphor: ReFantazio will awaken to their unique Archetype, which can then be utilized by other members. Early on, some join without immediate combat capabilities, but this changes as the story progresses and they awaken to their Archetypes before engaging in battles.
Storhl - Warrior
Storhl is the first to join your team on 6/5 during the Border Fort events, though he won't awaken to his Archetype until the next day on 6/6 at the Nord Mines. Initially, he'll be AI-controlled until his awakening.
Grius
Grius joins after the Border Fort events but won't fight until 6/6. After Storhl awakens, you can assign an Archetype to Grius, making him a regular party member, though he won't have a unique awakening.
Hulkenberg - Knight
Hulkenberg begins interacting with the party on 6/10, but won't fully join until her Archetype awakening during the boss fight on 6/11.
Heismay - Thief
Heismay's recruitment starts during your free time in Martira. You'll witness his awakening and subsequent joining on 7/4 after entering the main dungeon of the town.
Junah - Masked Dancer
Junah, though visible throughout the game, won't join your party until her awakening on 8/13.
Eupha - Summoner
Eupha offers flexibility in her recruitment. During your free time on Viraga Island between 8/19-9/4, completing the Dragon Temple Dungeon will lead to her joining for the final boss. Her Bond can only be initiated after the deadline.
Basilio - Berserker
Basilio awakens and joins during Saint's Day on 9/11, but you won't be able to use him in combat until the following day.