Sub Trope of Defeat Means Friendship.

In a normal Defeat Means Friendship scenario, someone formerly opposed to the hero joins their side or at least becomes more affable towards them shortly after being defeated by them. In this trope, the defeat is the sole reason for their Heel Face Turn. The defeated character effectively says, "Okay, now that I know you're stronger, I'm gonna join up with you now. " The reasons for this varies:

• They're a Proud Warrior Race Guy, Blood Knight, or other character type that admires strength. Since you proved to be stronger than them, they respect you enough to want to help you.
• They're an opportunistic Reliable Traitor who feels that his/her interests would be better served on the hero's side.
• They wanted to join the hero's side all along. They just wanted to test the hero's power first
• They're a Dirty Coward who doesn't want the hero to finish them off.

Examples:

• King Bulbin from The Legend Of Zelda: Twilight Princess is the Trope Namer
• Grobyc from Chrono Cross is this.
• Stratos 4:

• In Farscape there is a human alien that betrays her people because of this more or less.
• Warcraft3 has Varimathras, a Dreadlord who repeatedly switches sides, and who even has "I'm always on the winning side" as one of his responses.
• In Destiny of an Emperor, Lu Bu decides to serve Yuan Shao upon seeing how big and powerful his army is.
• Blazing Saddles. After Sheriff Bart has defeated Mongo:

• Kenpachi Zaraki in Bleach eventually does a Heel Face Turn (sort of, its complicated) and decides to help out Ichigo and his Nakama, on the basis that if Ichigo survives, Zaraki will get to fight him again.
• In Kill Zone, ISA gets a good deal of traitors amongst them throughout the invasion of Vekta, Adams shut down the defense line that allowed the invasion to happen and the Colonel allowed nuclear weapons to fall into enemy hands.