DARK KNIGHT Edit
Fighter's Spirit: This works as the listed ability. It possesses no additional effects.
Challenge: The dark knight gains an additional number of times per day it can challenge as granted by leveling up.
Dark Knight Bonus Feats: Dark Knights gain the bonus feats as usual, however they only gain them at levels 5, 13, and 19.
Executioner: This ability can be used an additional time per day.