Soul Calibur III was the series’ final installment on the PS2, and the last to have an arcade release; SC IV was only on home consoles, and there are no plans for SC V to be released in arcades, either.
Unlike Soul Calibur II, SC III was only ported from the arcade release to the PlayStation 2; this did away with all of the system-specific bonus charcters. Namco added three new characters: Zasalamel, an immortal Egyptian with a huge scythe, Tira, an insane girl with a giant chakram, and Setsuka, a blonde woman trained in battoujutsu.
Sure, the weapons, costumes, setting, characters, and premise might be completely outlandish, but who cares? You get to pit ninja against knight, sword against staff, and hero against villain! It’s what video gaming is all about!