Alright, a few things. Dorn and Nik forget the Bless adding +1 To Hit and that Devil’s Bane provides Good Alignment, +2 Enchantment, +2d6 damage.
Nik, you also should have rolled a Caster Check to overcome SR. I rolled 16+6=22. Passed.
Also Nik takes an AoO, for 13 damage.
CN41 is a table, so Nik only makes it to CO41, and Dorn to CP41.
Sirfinn, you cannot take Full Attack with movement, so the second attack will be discarded.
I rolled the Devil’s Bane damage, Nik got 8, Dorn 5 = 13 damage. Total Damage or Pit Fiend = 52. He falls, but combat is not over yet.