These days, thinking on the Ys series in general, and recalling Adol's adventures, and all equipment sets one acquires, it came to me that Adol could be considered pretty much THE swordsman from RPGs. I say this because in comparison to other RPG MCs like Cecil Harvey, Cloud Strife, Lloyd Irving, Yuri Lowell, etc., Adol has been on the most number of adventures. I doubt Ys IX is the last chapter since the often referenced adventure logs of Adol himself allude to him having written experiences of many more adventures that we've yet to see. From Ys I to IX, one can see his growth as a character, and as one who knows his way with a sword. He's faced numerous fearsome foes, and has helped solve near-world-endangering crises. He's received the blessings from numerous deities across different lands, and it would seem that since the very beginning he has always been some sort of proxy to the deities themselves (specifically the Gods revered in the
Tritheism religion within Ys). Sure that, in some of his adventures he's had the help of other strong individuals (such as his best friend Dogi, who has accompanied him since Ys I), but the plot of all entries moves forward with Adol at its center.
On the matter of how would him being included in Smash Bros. Ultimate be seen by most people, I fear that they would brush him off as just another swordfighter, and that is truly a shame. From the outside, that's what he appears to be, but those who've played through a number of the Ys games know that he can do much more than just swing a sword. On the first page of this thread there's some potential movesets that could be implemented from some of his games that would set him apart from being "just another swordfighter".