—Edelgard, to Byleth
"Just a minute! The following section contains spoilers, viewing it will cost a lot. Are you prepared to pay for it?"
If Byleth chooses to side with Edelgard against the Church of Seiros, they will retreat from Rhea to an Imperial camp nearby. There, they rally the students of the Black Eagles house, and establish a unit capable of acting independently from the main Imperial army. After Byleth seemingly vanishes in one of Rhea's attacks as the Immaculate One, the Black Eagle Strike Force spends the next five years in prolonged conflict against the Holy Kingdom of Faerghus and the Leicester Alliance, though miraculously suffering no casualties. On the day of their promised reunion, Byleth returns to the monastery, is greeted by Edelgard and promoted to Commander of the Strike Force. With the return of their professor, Edelgard and Hubert plan on breaking the stalemate of the war by defeating and capturing the Alliance before fighting the Kingdom and Church.
- Byleth Eisner - The former professor of the Black Eagles House at Garreg Mach Monastery and commander of the Black Eagle Strike Force.
- Edelgard von Hresvelg - The ambitious and determined emperor of the Adrestian Empire. She fights alongside the Black Eagle Strike Force despite her position.
- Hubert von Vestra - Heir to the late Count Vestra and Edelgard's devoted vassal since childhood. Cold and calculating at the surface, he conceals the honorable motives of his schemes and sinister countenance.
- Ferdinand von Aegir - The competitive and industrious former heir to House Aegir before his father Duke Aegir was stripped from his belongings.
- Linhardt von Hevring - The carefree heir of House Hevring who goes out of his way to shirk responsibility. Has a keen interest in the nature of Crests.
- Caspar von Bergliez - The second son of House Bergliez. Being unexpected an inheritance, he plans to make a name for himself as a general in the strike force.
- Bernadetta von Varley - The shy and withdrawn daughter of Count Varley. Though the Count is on house arrest, she supports the emperor's decision and feels safe with her.
- Dorothea Arnault - One of the few commoners among the ranks, she was a former songstress for the Mittelfrank Opera Company.
- Petra Macneary - Princess of Brigid who wishes to remain allies with Edelgard and the Adrestian Empire for the future of her kingdom.
- Jeritza von Hrym - Born to Baron Bartels before being taken into House Hrym, the infamize Death Knight now serves the emperor as a general.
Any students and/or staff members from Garreg Mach that Byleth has successfully recruited are also among the ranks of the Black Eagle Strike Force. The exception is Flayn, who returns to the Church of Seiros shortly before the team is formed. They are as followed:
- Felix Hugo Fraldarius
- Ashe Ubert
- Sylvain Jose Gautier
- Mercedes von Martritz
- Annette Fantine Dominic
- Ingrid Brandl Galatea
- Lorenz Hellman Gloucester
- Raphael Kirsten
- Ignatz Victor
- Lysithea von Ordelia
- Marianne von Edmund
- Leonie Pinelli
- Hanneman von Essar
- Manuela Casagranda
- Alois Rangeld
- Shamir Nevrand
- Yuri Leclerc
- Balthus von Albrecht
- Constance von Nuvelle
Additionally, during the capturing at Derdriu, Lysithea can be recruited among the Black Eagle Strike Force even if she wasn't recruited during the Academy phase.
- Seteth, Flayn, Cyril, and Catherine have unused artwork depicting their S-Supports with Byleth in the Crimson Flower route, suggesting that they were initially able to join the Black Eagle Strike Force but were later scrapped. Additionally, Hilda has unused data for her S-Support during the Crimson Flower route, suggesting she was at one point planned to be recruited as well.