Replacement characters are a fan term used to describe a type of playable unit that appear in Fire Emblem: Shadow Dragon if the player suffers many losses - so much that they have less than the maximum number of units allowed for the current map in their entire army.

These characters have no face sprites and use the generic class icons. Their names are fixed (chosen from a bank of 31 names) and depend on the language version. For instance, the Japanese replacement characters are named after German numbers, days and months. In the North American version some of the characters come with humorous, derogatory names, such as "Lucer", "Auffle",and "Wymp".

They have no stat additions (meaning their base stats are equal to the class base stats) or growth rate additions (so their growth rates are equal to the playable class growth rates) so they are typically inferior to regular playable units. Additionally, their lack of a luck stat makes them prone to enemy criticals.