For April Fools' 2017, a new game called "Fire Emblem: Battle of Revolution" (Japanese: ファイアーエムブレム 維新大乱) was announced, for the Nintendo Switch and Nintendo 3DS. It prominently featured Valbar, Kamui, and Leon. It takes place in the Edo period of Japan. Some text on the website is in traditional vertical writing, and all character and location names were written in kanji with the katakana names as furigana. DLC featuring Marth was also announced for "Battle of Revolution". There would also be scrolls as a limited bonus. It was stated to be released on April 20, 2017, the same date as Shadows of Valentia. There was also Marth DLC

Tuesday Trivia:

Fire Emblem Awakening's Japanese-only "Background" website featured several exclusive character illustrations and some bonus dialogue for scenes not appearing in the game.

Tuesday Trivia:

As revealed in a developer interview, it was at one point planned for Awakening to have the map sprites drawn at different resolutions for different camera zoom levels. This is also the earliest known image of the game.

Tuesday Trivia:

Early footage of Awakening had different Critical Hit cut-ins. (Left-early, Right-final)

Tuesday Trivia:

Marth does a sweet backflip when using Falchion in Dark Dragon and the Blade of Light

Tuesday Trivia:

Early promotional footage for Shadows of Valentia featured impossible unit states, such as Silque as a Sage, and Mae being able to cast Excalibur.

These were likely achieved through use of a developer debug menu, and only occurred in the English version of the trailer.

Tuesday Trivia:

In the earliest Path of Radiance screenshots, Ike was named "Paris" (パリス). Priam in Japanese Awakening shares this name, likely an intentional reference.

Tuesday Trivia:

Official artwork exists for some of the monsters from Fire Emblem: The Sacred Stones. However, it was only seen at low resolution in some magazine coverage of the game and on the now-defunct Fire Emblem Museum website.

Tuesday Trivia:

Roy had a different design in the very earliest footage released for Fire Emblem: The Binding Blade. He appeared younger and more energetic, and with poofier hair

Tuesday Trivia:

There is a leaflet for Fire Emblem: Mystery of the Emblem that featured glorious pantsless Marth. Unfortunately, he was given pants in all subsequent artwork for the game.

Tuesday Trivia:

Darios has unused map sprites in the player palette. This is atypical of enemy/npc only characters, like Gharnef, Iago and Validar. Developer interviews confirm he was planned to be playable in an update, but scrapped.

Tuesday Trivia:

Several batches of concept sketches for The Binding Blade were shown on the Fire Emblem Cipher official website and in streams

Today (December 26 JST) is the 7th anniversary of Tokyo Mirage Sessions ♯FE, which released on the Wii U in 2015 in Japan.

Tuesday Trivia:

Elincia's pegasus was once owned by her great grandmother. He's apparently a very old horse!

Will the wiki finish transparenting the Berserker class article thumb-box image?

There isn't a dedicated image cleanup task force, or anything, but I'll let the editors know!

Fire Emblem Engage sticker sheet, included with preorders in certain regions (once again, thanks to @galladeknight31 for pointing this out) No notable new faces here, though this is our first glance at Sombron's sprite I think (spooky dude in the bottom right)

Tuesday Trivia:

Gerome is the one that gave Lucina her butterfly mask