Enemies Turned Friends

Sometimes the main antagonist redeemed themselves after seeing the goodness of the heroes and heroines or realize that being evil is a bad thing after betrayal, etc (that depends on them). It's similar to redeemed or misunderstood heroes...

Here's why we should turn the enemies by becoming friends A version of Negativity turned Positivity and Hero's Redemption.
 * by showing them that being evil is very bad thing and they should redeemed themselves someday
 * when the main antagonist sometimes hang out with the main protagonist, they realize that they're getting soft and don't know what to do
 * Sometimes the main antagonist realize that heroes were right about them by telling them that they have some goodness inside them which they didn't know all along since they have been enemies for years
 * Sometimes, the enemy can be a friend of the hero, placed under a curse which is turning them evil, and the hero manages to break the curse, restoring their friendship.
 * The enemy's pawn ends up killing the main antagonist officially redeeming himself (ex. Iago kicking Jafar's lamp into molten lava, destroying him once and for all.)

Examples

 * Marge Simpson and Lindsey Naegle become friends after a conflict dealing with children
 * Woody decides to help Buzz Lightyear from Sid.
 * The conflict between Lois Griffin and Joyce Kinney ends after the events of Season 9.
 * Joshua Joyce decides to join Cade Yeager for save the world from the extinction.
 * Vegeta giving a thumbs up at Goku and becoming friends with him after Goku defeated Kid Buu.
 * Iago fully accepted into the palace for destroying Jafar once and for all.
 * Discord learning that he would lose the only friend he ever had and something he doesn't want to lose, then leads to his first redemption. Then after realizing that Tirek manipulated him this whole time, he understands there's nothing more worth than friendship, leading to his second and full redemption.
 * A fully redeemed Peridot joins the Crystal Gems.