Hercules and Iolaus
First Meeting: Prior to the events in Young Hercules (Movie Pilot)
Status: Started out as foes who became as close to being brothers as two men can be without actually being related
History: From the way Hercules and Iolaus interact toward each other in the beginning of the series pilot, it can be gathered that they did not necessarily start out as friends. If anything, Hercules seemed to find Iolaus to be more of an annoyance than an ally. Toward the end of the pilot, though, they have bonded and become (with a bit of resistance on Hercules's part and some enthusiasm on Iolaus's) friends. This would carry over into the series proper, which shows them obviously getting along and treating each other as equals instead of rivals.