Looking for a specific Fighting Game

When I was a kid, I played a fighting game where there was a mode where you'd be on a sort of map and you'd fight and collect different types of weapons. You could choose characters and whatnot, unlock stronger weapons etc. I remember there being one guy who started with a weapon where the stats where all coloured and maxed out, suggesting you can't get any stronger weapon anyway, so it kinda felt pointless.

I also remember my brother explaining one of the character's "story" was that in the end he got poisoned by the poison he put on his own weapons accidentally.

I want to say it's one of the Soul Calibur games but I haven't really found it. This may sound obscure but if you've played this specific game, could anyone tell me what it was? I'm going nuts trying to figure it out.