Oh boy, it's time for me to make a...
Nihon Falcom is a surprisingly old Japanese game dev company (their first game was in
1982 for the PC-8801!). They're most known for the Ys and Legend of Heroes: Trails franchises, although they have some other games too (Tokyo Xanadu and Gurumin: A Monstrous Adventure come to mind). Trails is their big turn-based RPG franchise, while Ys is their big action RPG franchise. The three characters that could feasibly be included in a crossover game like Smash are Estelle Bright and Rean Schwarzer from the Trails series, and Adol Christin from the Ys series.
Starting with Ys (pronounced like "geese" without the G), this is their big action RPG franchise, starting on the PC-8801 in 1987. Since then, there have been a couple different gameplay styles it's gone through, but overall the focus is on fast, tight combat. All of the Ys games (minus the prequel game, Ys Origin) star Adol Christin. Depending on the game, his moveset/abilities change. The first two Ys games have what's called the "bump system." While I haven't played those, I believe it's like the Impact Run ability, where you damage enemies by charging into them. Later Ys games give him a bunch of skills that you can assign to inputs, kind of like Tales arts. They also introduce Flash Move and Flash Guard, which are essentially perfect dodging and parrying, but they provide temporary bonuses when pulled off (Flash Move slows down enemies and Flash Guard boosts your damage).
As for Trails, this is their big turn-based RPG franchise, with super in-depth world-building and phenomenal character writing. Y'know how Persona kind of branched off from SMT into its own thing? Trails did that twice. The first Trails in the Sky game is the sixth entry in the Legend of Heroes series, which itself started as a spin-off of the Dragon Slayer series, and the Dragon Slayer series started in 1984. There are three major Trails story arcs: the Sky arc (Trails in the Sky, Trails in the Sky SC, and Trails in the Sky the 3rd), the Crossbell arc (Zero no Kiseki and Ao no Kiseki), and the Cold Steel arc (Trails of Cold Steel I-IV). (There's also the currently Japan-only Hajimari no Kiseki as kind of a spin-off/epilogue to the three arcs.) Estelle is the protagonist of the Sky arc, and Rean is the protagonist of the Cold Steel arc. One thing about Trails' storytelling is that all three arcs take place on the same continent within a few years of each other, so even though Estelle is the protagonist of the Sky arc, she and other Sky characters are involved in later arcs as well.
In terms of abilities, Estelle uses a bo staff, while Rean uses a sword called a tachi. Both can also cast a large variety of spells. I mentioned a little bit ago about what gimmicks they could use for Estelle, and the same could be said for Rean. Rean can also (end of Cold Steel I)
summon a big ol' robot and climb inside for some fights.
Including any Falcom character would be super interesting from a historical perspective, mainly because of just how far back these franchises go. Ys in particular was one of the earliest action RPG franchises, but The Legend of Heroes also made its own mark with its crazy world-building. Recently, now that NISA has taken over publishing instead of XSeed, both franchises have been coming to Switch and have upcoming releases -- Ys VIII and Trails of Cold Steel III are both on Switch already, and Ys IX and Trails of Cold Steel IV are on their way to Switch next year. If they went with Trails, Rean would be a very Joker-esque pick in terms of his role in the series, since he's the protagonist of the newest arc, but Estelle would be more Terry-like, being the
face of the franchise to some extent.
The music also slaps (
exhibit A,
exhibit B,
exhibit C,
exhibit D,
exhibit E), and since it's all kept in-house under the Falcom Sound Team jdk label, it's very possible that regardless of which franchise gets chosen, we'd get a big selection of tracks from both. My top pick from Falcom is Estelle, since I really enjoy her character, and think she'd do a good job representing the Trails franchise as a whole, but I would be excited to see any Falcom character make it in.