Bond Units are a gameplay mechanic introduced in Fire Emblem Fates. When giving an accessory to another player at their My Castle, after having done so multiple times before, and having also received at least one accessory in return from that same player, a unit will be created. This unit is the "child" of the two players, resembling an Avatar that looks similar to the two who created it, such as having the same hair color or face type, distinguished by a mark on their cheek. They are not an actual child, as they can be created by two players of the same gender and the game announces them as being "born from the earth" due to the strength of the players' bond.