Vitriolic Best Buds/Tabletop Games

Examples of in  include:

Board Games

 * Warhammer 40,000 example: Leman Russ and Lion El'Johnson hated each other's guts for quite some time after their first encounter, in which the two primarchs ended up fighting each other over an honor issue, fueled by their vastly different personalities, but over time, they became accustomed to each other's personalities and eventually became very close friends. Their rivalries remained, however, so this is the kind of friendship that evolved. Their successors sadly only remember the rivalry part of their relationship, however.

Tabletop RPG
"1444. My Ally advantage and Arch Enemy flaw can't both represent the same person."
 * Things Mr. Welch Is No Longer Allowed to Do In An RPG, 1001-1500: