Soul Edge
The game that started it all, while not called SoulCalibur, Soul Edge is the very first entry in the weapon-based fighting series. Following Battle Arena Toshinden, Soul Edge was the second entirely weapons-based 3D fighter in history.
The game helped establish many of the elements the series would become known for. Movesets stuck fairly close to what you’d see out of Namco’s other big fighting game at the time, Tekken.
At the time, Soul Edge featured a more detailed story than your typical fighting game, actually giving context on each character’s motivations in the narrative.
We were also introduced to many of the series’ most iconic characters, although they looked quite a bit different at this time.
The roster consisted of Mitsurugi, Siegfried, Taki, Sophitia, Rock, Voldo, Seong Mi-na, and Li Long (who would only appear later as a bonus character in III).
It may not have aged all that well, but Soul Edge remains the basis for what would come later.