You need the "Loemendor" map
from here to view the fight.
the fight itself is nothing extraordinary - it's just two exceptional damage rolls. From the debug log:
221 striking with weapon Flail. att23 def28
shieldprot for King of Flames = 40
hitloc Flagellant strikes King of Flames wl3 diff2 -> 4
hitunit 221 16083 dmg-37 spec2097159 ba4
shieldprot for King of Flames = 40
hitloc Flagellant strikes King of Flames wl6 diff-1 -> 2
hitunit 221 16083 dmg-34 spec96 ba2
damage 36 on King of Flames, spec0x60 ba2
Trying to strike agains Awe 5 (mor 20)
1412 striking with weapon Flail. att17 def40
1412 striking with weapon Flail. att26 def30
shieldprot for King of Flames = 40
hitloc Flagellant strikes King of Flames wl3 diff2 -> 4
hitunit 1412 16083 dmg-37 spec2097159 ba4
shieldprot for King of Flames = 40
hitloc Flagellant strikes King of Flames wl6 diff-1 -> 2
hitunit 1412 16083 dmg-34 spec96 ba2
damage 32 on King of Flames, spec0x60 ba2
Going through the last one:
Trying to strike agains Awe 5 (mor 20)
1412 striking with weapon Flail. att17 def40
1412 striking with weapon Flail. att26 def30
Flagellant (unit nr 1412) succeeded against awe and strikes the King twice. I think the att26 and def30 values are the attack value of the flagellanbt and the def value of the king after random roll and some modifiers (stats etc) - but not all, because the flagellant did score a hit. Perhaps the def30 is with a shield?
shieldprot for King of Flames = 40
Protection with shield added.
hitloc Flagellant strikes King of Flames wl3 diff2 -> 4
hitloc -> head strike or body strike, most probably
hitunit 1412 16083 dmg-37 spec2097159 ba4
the attack would deal roll - 37 points of damage (with unit strength added afterwards?)
shieldprot for King of Flames = 40
hitloc Flagellant strikes King of Flames wl6 diff-1 -> 2
hitunit 1412 16083 dmg-34 spec96 ba2
I think this is the same thing for the head. As in, the first is the damage on a body hit, this on a head hit.
damage 32 on King of Flames, spec0x60 ba2
The result. The flagellant dealt a total of 32 + 34 = 66 or 32 + 37 = 69 points of damage. I don't remember what the flagellant's strength was, but in any case, he had awesome luck - about 10 rerolls on a virtual six-sided dice. Possible, but very rare.