Garreg Mach Monastery
Garreg Mach Monastery (ガルグ＝マク大修道院, Garreg Mach Monastery) is a downloadable stage in Super Smash Bros. Ultimate from the Fire Emblem series. It is based on the pivotal location of the same name and the primary setting of Fire Emblem: Three Houses. It was released on January 28th, 2020 as part of Challenger Pack 5.
The stage cycles through four locations. Transitions between each location have a mystical blue platform rocket the fighters upward, showing a view of the landscape, before plummeting back into the next area (showing damage to areas with ceilings). Like other traveling stages, it is possible to miss the platform as it appears and be KO'd at the bottom blast line. All locations of the stage have walk-off blast lines. The stage rotates through the areas in order and starts over after about two and a half minutes.
The first location is the Marketplace; the battle occurs at the bottom of the stairs. Two stalls are present on the far right and left of the playing area, respectively, which can be used as platforms but can also be destroyed by attacks. The Blue Lion House, represented by Dimitri, Dedue, and Ingrid, will watch the battle from the sidelines; the Gatekeeper can also be seen at his post at the top of the stairs.
The second location is the Reception Hall. The tables in the background can be destroyed if a strong enough attack is landed in front of them, like the signs on Suzaku Castle. Chandeliers hang above the fighting area, so high that certain fighters, including Byleth, cannot reach them on their own. Like the lighting fixture above Boxing Ring, these can be attacked to drop them on fighters below, dealing damage. The Black Eagle House, represented by Edelgard, Dorothea, and Petra, will watch the battle from the sidelines.
The third location is the Bridge. The Bridge is a simple, wide area with walk-off blast lines, comparable to the Bridge of Eldin. The Golden Deer House, represented by Claude, Hilda, and Lorenz, will watch the battle from the sidelines; a Pegasus Knight can also be seen doing flight drills in the background.
The fourth location is the Cathedral. Two semi-solid platforms float above the far left and right of this area; these will slowly move off-screen shortly before the screen transitions. The Church of Seiros, represented by Rhea, Seteth, and Flayn, will watch the battle from the sidelines.
In battles with more than four players, some of the cameo characters are omitted; only Dimitri, Edelgard, Claude, Flayn, Seteth, and Rhea will appear. Certain cameo characters will also be omitted in spirit battles of Three Houses characters if they are represented by a puppet fighter in said battles; for example, the Seteth spirit battle is set in the Cathedral but only Rhea is present in the background, as Seteth and Flayn are represented by puppet fighters in that battle.
Ω form and Battlefield form
The Ω form and Battlefield form take place in the area where the Bridge normally is. The main platform resembles the floor of the Cathedral in the normal form, but is resized and reshaped to match Final Destination and Battlefield, respectively. The three soft platforms of the Battlefield form are the same as the two soft platforms in the Cathedral. The stage also does not cycle through the four areas, and cameos do not appear at all, unlike Mementos, Spiral Mountain and King of Fighters Stadium and like Animal Crossing stages. Prior to 8.0.0, the Battlefield and Ω forms of Garreg Mach Monastery had a lower ceiling than Battlefield, Final Destination and other Battlefield and Ω forms. 
With Hazards off, the battle remains in the Cathedral for the duration of the match. The two floating platforms will periodically move offscreen before returning.
The Garreg Mach Monastery serves as the central hub for the first part of Fire Emblem: Three Houses. At the start of the game, Byleth is hired to be a professor at the Officer Academy that's located there, and can choose one of the three houses to represent; the house chosen affects the path the game would take in the second half of the game.
The Marketplace is where Byleth can buy or sell weapons and other items for their house to use. The Gatekeeper, a minor non-playable character, stands guard in front of the monastery gates and discusses the game's events with Byleth when spoken to.
The Reception Hall is one of the main rooms of the monastery; students and faculty gather here for events such as the White Heron Cup and the grand ball that follows after.
The bridge serves as a pathway to the cathedral, where priests, students, and faculty gather to pay homage to the goddess of Fódlan. The cathedral is also where Byleth can provide guidance counselling for their allies via a suggestion box to increase support points, have two chosen allies participate in choir practice to increase their proficiency in faith magic, and use their accumulated renown to repair the saints' statues that give army bonuses.
In the Crimson Flower route, Edelgard von Hresvelg has captured the monastery and uses it as the Adrestrian Empire's base of operations by the time Byleth awakens from their five-year coma. In all other routes, it has become a haven for thieves; Byleth must team up with their chosen house leader (or Seteth if they chose not to ally with Edelgard in the Black Eagles route) to drive the thieves out and reclaim the monastery as their base of operations.