Relay Defense (Japanese: リレー防衛戦 Relay Defense Battle) is a game mode in Fire Emblem Heroes, and one of a number of types of the game's Special Maps. It is a type of Special Maps that debuted on September 8, 2018, and whose maps rotate on a schedule intertwined with the Rival Domains mode; Relay Defense maps use Relay Defense: Event Map, last for two weeks, and their events begin and end on Saturdays at 7:00 AM UTC.
Relay Defense takes place on larger game maps than normal gameplay, and allow players to deploy teams of up to 20 characters, of which up to five can be on the map at any given time. At the start of every odd-numbered turn, the units the player has on the field at the time are switched out and replaced by the next five characters in line in the same locations, or back at a player's base if one of the units in the quintet being switched out had been defeated. There are some restrictions on character deployment, namely that players may deploy a maximum of one character that can use Sing or Dance and cannot deploy duplicate characters.
Forming a brigade
Much like Rival Domains and Grand Conquests, in addition to their own characters, players also have the option of deploying characters chosen by those on their friend lists; the character at the top left of a player's first listed team is the one made available to other players. If a player leaves empty slots in their deployment, any missing slots will be filled with a randomly-selected 5★ character chosen from all normal-variation characters available in the regular summoning pools that do not wield staves, Sing, or Dance.
Unlike other types of Special Maps, the enemies on Relay Defense maps are randomly generated more in the vein of the Tempest Trials, also taken from all normal-variation characters minus performers and staff-wielders in the regular summoning pools, but the enemy army ignores the "no duplicates" rule and fixes its selection to those characters available when the map most recently rotated in (ex. the the Event 1 maps did not include Ophelia, Nina, Silas, and Flora as available enemy units as they did not become available until after the map started, but did allow those four characters as player reinforcements as the player reinforcement pool is not bound by the same rule). The enemy army has only twelve units in total, with six present on turn 1 and the other six arriving as reinforcements on turn 2.
The player's team can make use of two types of special tiles to their advantage, fortresses and camps. Characters can freely warp between fortresses, camps, and three chosen squares adjacent to them. Fortresses can be taken out with three attacks, if the enemy team does so, the battle automatically ends as a loss for the player; camps can be taken out with two attacks, and when this happens, the camp will no longer be usable.
To win a Relay Defense battle, the player's fortress must remain standing throughout all eight turns. The player can accumulate a score during a battle; points are awarded for defeated enemies, surviving allies, the health of the fortresses and camps, and bonus categories that vary per map, and meeting the target score yields rewards.
Relay Defense has eight "difficulties" available across its eight maps, each one requiring the previous map to be defeated in order to access:
|Enemy skills||Enemy stat boosts||Rewards|
|1st Map||3★, Lv. 30||Fourth weapon skill and Pivot only||None||×1|
|2nd Map||4★, Lv. 35||Highest weapon skill and Pivot only||HP +5||×500|
|3rd Map||5★, Lv. 40||Entire skill kit, apart from assist skill which is always Pivot||HP +10
Attack/Speed/Defense/Resistance +2 each
|4th Map||Entire skill kit, apart from assist skill which is always Pivot
Weapon skills have gone through the Weapon Refinery whenever possible
Attack/Speed/Defense/Resistance +4 each
|5th Map||HP +15
Attack/Speed/Defense/Resistance +6 each
|6th Map||HP +15
Attack/Speed/Defense/Resistance +8 each
|7th Map||HP +15
Attack/Speed/Defense/Resistance +10 each
|8th Map||HP +15
Attack/Speed/Defense/Resistance +12 each
List of maps
- Note: All date ranges begin at 7:00 AM UTC on the first listed date and end at 6:59 AM UTC on the second listed date.
|List of Relay Defense maps|
|Map 1/3/5/7||Map 2/4/6/8||Notes|
|Event 1||September 8, 2018-September 22, 2018||--|
|Event 2||October 13, 2018-October 27, 2018||--|
Etymology and other languages
|Names, etymology and in other regions|
|Language||Name||Definition, etymology and notes|
|Japanese||リレー防衛戦||Relay Defense Battle|
|Spanish||Def. por relevos||Relay Defense|
|French||Défense en relais||Relay Defense|
|Italian||Difesa alterna||Alternative Defense|
|Traditional Chinese||接力防衛戰||Relay Defense Battle|