Settings at end of video.
Deathbringer is the clear choice in this game, his HCB+C is hilarious and can be charged while opponents are down. This can easily be sub-5 but too many games to look at right now. Final boss was almost perfect, so I'm taking this run. I had one that reached Deathbringer at around 3:30 (need excellent RNG) but in that run I died to him as I hadn't found a consistent strat for him yet, so I ended up with like a 6:40.
For time, I used the first frame of the KO graphic appearing on screen. Since we don't use ms for this game I figure that's probably accurate enough.
Played on JP slim PS3, NA region copy of the game, Used Qanba Obsidian (PS3 mode). None of that should affect anything, I don't think? The game basically has no loads so I doubt there's a meaningful difference between platforms in that regard.