Here's the swiftest history of Fire Emblem Gaiden and Fire Emblem Echos I can come up with. Fire Emblem Gaiden first came out on the NES in Japan March 14 of 1992 and never made it to Western shores. Of all the Fire Emblem games, Gaiden, though only being the second game in the series, has always been thought of as the odd game out, including a myriad of features to never appear in the series again such as 3rd person dungeon crawling and explorable towns. In addition, Fire Emblem Gaiden also had many mechanic elements which were not repeated: spells are learned through leveling up rather than dispensed through tomes and characters may only carried one item at once, the classic Fire Emblem weapon triangle was also mysteriously excluded from Gaiden. In this aspect, Gaiden remains one of the more unique entries in the series. Because of it's obscurity, no one was ever expecting Gaiden's story to ever make it to western shores, outside of fan translations, but then Fire Emblem Echoes: Fires of Valentia was announced for the 3DS. FE: Echoes is a a complete remake of Fire Emblem Gaiden, though the game maintains its same story and characters, the dialogue, among other elements, has been slightly tweaked.
Leon is an archer in Fire Emblem Gaiden. His backstory goes a little something like this: Leon was once a soldier in the Nation of Rigel's army where he falls in love with a soldier who dies in the heat of battle. Leon is distraught and falls into a deep depression. After some undisclosed amount of time he meets then meets Valbar, a Rigelian knight who encourages Leon to get back on his feet. Leon develops feelings for Valbar and vows to follow Valbar wherever he goes as his sworn "brother". This is the narrative Gaiden wove into what I believe to be the first Queer character in the Fire Emblem Series. I think it's hard to consider this backstory as having "homoerotic undertones" as undertone suggests that this story is the slightest bit subtle and it really isn't. Leon is canonically confirmed as having been in love with two men in the course of his life. But back when I was first playing a fan translation of Gaiden, the argument was made that I was reading too far into the subtext. But with Echoes, my theory was confirmed.
For spoiler's sake I will not quote him directly but several times Leon admits that his love for Valbar is romantic rather than platonic throughout Echo's support conversations. He also says this to Valbar and Valbar accepts it, without the stereotypical straight man disgust or drama.
Such a tasteful treatment of these themes seems radical when you first think about it, but in reality, it's not so much. Video games for many years have had characters who are Queer. Some of these characters are offensive and saturated with stereotype but some fly under the radar. For Pride month my intention is to remember some of these characters and honor them.