Nintendo has updated the official Japanese website for Fire Emblem Echoes: Shadows of Valentia, which has new artwork for many of the game's recruitable characters, as well as some gameplay snippets.
Character art is in the gallery below. These are, in order:
Alm's Route: Grey, Tobin, Cliff, Efi, Silque, Clive, Lukas
Celica's Route: Mae, Boey, Leon, Saber, Genny, Valbo, Kamui
Most of these characters are from the original Fire Emblem Gaiden. Efi, however, is a new addition to Fire Emblem Echoes and is Alm's childhood friend. [Update: Efi's English name is Faye, likely to differentiate from Fire Emblem Fate's Effie.] Another new character, Berkut, was detailed in the latest issue of Famitsu. (his art was provided in the original announcement).
Famitsu also provided a few further details on the game's systems. There will be a Normal/Hard difficulty toggle as well as a Classic/Casual 'permadeath' toggle - similar to recent games. Since there is no weapon triangle, terrain effects will play a key role in battle strategy. Placing a unit on a forest lowers enemy accuracy by 40%, for example. Magic negates these sorts of terrain effects, but will drain the caster's HP.
Silque holds the unique item "Mila's Gear", which can 'rewind' turns, although there is a limit to its use.
Nintendo posted a few short gameplay clips on the game's website:
Finally, we collected some screenshots from PAX previews and Japanese retailers and placed them in the gallery below. Fire Emblem Echoes: Shadows of Valentia launches in North America and Europe on May 19.