—Seliph asking the Avatar about their mark in Fire Emblem Awakening
The Brand (Holy Mark in the Japanese version) is a plot point recurring throughout the Fire Emblem series, originating as an in-universe explanation for the Holy Blood mechanic introduced in Fire Emblem: Genealogy of the Holy War. The Brand is a sign of a blood covenant between a powerful dragon and a human, passed on to the human's descendants. The humans who inherit the Brand are capable of harnessing the dragon's power via use of divine weapons and potentially can serve as a vessel for the dragon's spirit.
The Brand only manifests on those who inherited large amounts of the dragon's holy blood, though the full requirements for the inheritance is not known as manifestation of the Brand can skip generations or even not appear at all for a period of time. The Brand can manifest anywhere on the holder's body.
The Brand is introduced in Genealogy of the Holy War as a sign of descendants of either Galle or the Twelve Crusaders that have inherited the Holy Blood of their ancestors and are capable of wielding their respective divine weapon.
In Fire Emblem Awakening, Chrom, Emmeryn, Lucina, and Owain possess holy markings as proof of their bond with Naga called the Brand of the Exalt, which allows them to wield the Falchion. A Chrom-fathered Inigo is noted to have the brand in the opposite eye as Lucina, although the brand does not appear on his critical cut-in art, nor can he wield Falchion or Paralell Falchion in gameplay. Strangely, none of Chrom’s other possible children seem to have a brand, even though the Lucina-Sibling support implies that any of her possible siblings may be able to wield the Falchion in story, although like Inigo, they cannot wield either Falchion in gameplay. Morgan does not have a brand when mothered or fathered by any other member of the royal family, nor can he or she wield the Falchion or Paralell Falchion in gameplay. Robin also possesses markings from Grima, known as the Brand of the Defile, which marks them as a potential host for the Fell Dragon, but Morgan does not inherit this brand.
In Fire Emblem Fates, Owain, under his alias Odin, can father a daughter named Ophelia who inherits the Brand of the Exalt. In Hoshidan Festival of Bonds, and Odin fathered Shigure and an Ophelia mothered Kana are noted to have the Brand of the Exalt as well.
In Fire Emblem Echoes: Shadows of Valentia, Alm was born with the Brand of Duma on the back of his left hand, while Celica was born with the Brand of Mila on her right palm, proof of their families ties to Duma and Mila respectively. These Brands were said to tie to a prophecy that when the individual Brands surfaced on a Rigelian prince and a Zofian princess, the reign of Duma and Mila on Valentia would end. The Valentia Accordion would reveal that Alm's father Rudolf also has the Brand and that holding of the Brand of Duma allows the wielder to wield the Falchion.
TearRing Saga Series
In Utna Heroes Saga, Utna and Garlon's four daughters are the progenitors of the royal dynasties and priestly families of Reeve, Leda, Salia, and Canaan. Among these descendants, certain women called shamans (巫女 miko) occasionally arise, who, have inherited the power to shapeshift into one of the Guardian Dragons (Muse, Kranion, Neuron, and Rachis). These powers indirectly derive from the emiyu Miradona, who gave Utna some of her blood to drink to fight against Kalbazan, who had also drunk her blood. The shamans are capable of utilizing special bracelets that help them control their draconic power and awaken the sleeping fragments of Garlon's blade, which had also been blessed by Utna.
In Berwick Saga, descent from ancient Lazberians (that is, Zoans) is considered divine, as they were called the Sons of Gods (神の子ら kami no kora). In the Kingdom of Veria, the most honored bloodline is that of High Priest Aramgraz's granddaughter Valentia, the first Apostle. Generally, only well-learned individuals with Lazberian ancestry are entrusted with the secrets of using magic, and it is said that only those of such ancestry are even capable of using it.