Definitely Emperor or Rager Berserker.
If you look at warriors with 250+ kills, all of them were either Emperor or Berserker except for Igbah. I could reasonably argue that Igbah would have had even MORE kills as Emperor than he did as "scion non-mage".
If you instead look at PKpH, there are several outlanders near the top. (Mostly played by Marcus). However, I'm led to believe that certain aspects of Outlander powers were different back then that gave these characters an advantage they would no longer enjoy.
The other top warriors in PKpH were ragers, and almost all the ones at the top had less than 150 hours. If you look at "top warriors by PKpH who lived over 350 hours" then you get this:
Djabree (rager berserker)
Kostyan (emperor)
Granaak (scion)
Blitzenturt (emperor)
Sylus (empire)
Bartis (rager berserker)
Igbah (scion)
Ghrummin (rager berserker)
Yuvralin (rager berserker)
Hunsobo (emperor)
Personally I feel like the Scions in that list are anomalies, and that their players would have had more kills with Emperor (or possibly even Elite Blade) powers.