The Light Brand (光の剣, Hikari no Ken, translated as the Light Sword in the Japanese versions) is a recurring magic sword in the series. It has the ability to perform ranged attacks, which are treated as light-based magic attacks (the spell animation is the same as the Light TomeLightning), as well as direct attacks, which are treated as regular physical attacks. It is analogous to the AnimaWind Sword and the DarkRunesword, although it doesn't have any other side-effects like the other two do.
Indirect combat will be a light-based magic, using half your strength stat; direct combat will be a physical sword attack. In Sacred Stones, checks against Resistance for both direct and indirect. Uses normal sword weapon triangle placement for melee in all games, and light triangle placement for indirect attacks.
In Fire Emblem: Binding Blade, there is only one Light Brand available from a chest in Chapter 8, unless you gain access to Chapter 23, where there will be an armory selling Light Brands.
In Fire Emblem: Rekka no Ken, it is wielded by the assassin Jerme in Chapter 25: Pale Flower of Darkness (If certain conditions are met). You can get it by killing him. There is also one located under the sands of the Nabata Desert, in Chapter 22: Living Legend.
In Fire Emblem: The Sacred Stones, it is obtained by keeping six of the eight Rausten knights alive in addition to the Rausten General and Mansel when you finish Chapter 19.