The Sacred Twins (双聖器, Sōseiki lit. Twin Holy Weapons) are two legendary weapons unique to each nation in Fire Emblem: The Sacred Stones. They were all used by the legendary Five Heroes in battle against the Demon King.
With the exceptions of Latona and Gleipnir, all the Sacred Twin weapons deal bonus damage to monsters. All can only be used by a character who has S rank in the weapon type, except for Sieglinde and Siegmund, which can only be used by Eirika and Ephraim.
- Grado: Gleipnir, the Dark Tome and Garm, the Black Axe.
- Renais: Siegmund, the Flame Lance and Sieglinde, the Thunder Sword.
- Frelia: Nidhogg, the Serpent Bow and Vidofnir, the Winged Lance.
- Jehanna: Excalibur, the Wind Blade and Audhulma, the Ice Blade.
- Rausten: Ivaldi, the Glorious Light and Latona, the Saint's Staff.
- Excalibur and Garm are the only Sacred Twins that cannot be wielded by a member of the royal family that housed it.
- L'Arachel is the only playable noble who has the potential to wield both of the Sacred Twins of her kingdom, as a Valkyrie, though she is unable to do both at the same time due to weapon ranking mechanics.
- Excalibur is the only Sacred Twin without a logical user among the player's army, as there are no Anima magic users from Jehanna. Innes and Tana are the implied users of Nidhogg and Vidofnir respectively, being the prince and princess of Frelia. Duessel and Knoll are the implied users of Garm and Gleipnir due to their ties to Grado's royal family. Joshua is the implied wielder of Audhulma as Jehanna's prince. L'Arachel as already mentioned is the implied wielder of both Latona and Ivaldi.