Friendly Enemy/Tabletop Games

Warhammer 40,000‍'‍s Orks have no concept of "friend," but they do have a word for "favourite enemy." During the Second War for Armageddon, Warlord Ghazghkull Mag Uruk Thraka found himself a proper nemesis in Commissar Yarrick, and when Ghazghkull captured him in a subsequent campaign he let Yarrick go (after the requisite amount of torture) so the planned Third War for Armageddon would be more entertaining. Ghazghkull considers Yarrick the one humie who knows how to fight, and has been known to kill any lackey who insults the commissar. After all, "good enemies iz 'ard ta find, an Orks need good enemies ta fight like they need meat ta eat an' grog ta drink." Note that this is entirely one-sided: Yarrick despises Ghazghkull and has vowed to pursue him to the ends of the galaxy to avenge the billions killed for his amusement.