Making a Deal with the Enemy

In some stories, the heroes or heroines has to make a deal with the enemy or someone who works for the enemy. Later in the story, the hero goes back on the deal or keeps it.

This is often a result of working undercover with the enemy or trying to protect them for their own good.

Here's why they make a deal with a villain:
 * By protecting their love ones.
 * Sacrifice their own choice.
 * Decide to give up for being good and want to be evil for no reason.
 * Decide to give up their own lives and be something that they're not.

Examples

 * RJ makes a deal with Vincent that he will collect all of the lost food within one week, or Vincent will kill him.
 * Hercules gives up his strength for Meg's safety.
 * Itachi make a deal with Madara (whom actually Obito whom works as Madara's executor) to help him slaughtered Uchiha clan whilst sparing Sasuke.
 * Ariel deals with Ursula the Sea Witch that she's got three days to get Prince Eric to kiss her, and remain human. If Ariel doesn't kiss Eric before the sun sets on the third day, she turns back into a mermaid and becomes Ursula's prisoner.
 * Leonardo, Michelangelo, Raphael and Splinter, also Leatherhead make a deal with Agent Bishop for curing their brother Donatello, unless they Infiltrate Foot central for a relic.
 * Shrek makes a deal with Lord Farquaad that all fairy tale creatures will be returned to their rightful homes and his swamp will be back the way it was if Shrek and Donkey rescue Princess Fionna.
 * Shrek signs a magical contract with Rumpelstiltskin, so he can have a day to "feel like a real ogre again".
 * Lennox and some lawyers meet with Megatron to negotiate the return of several Decepticons to accompany him and Barricade in locating the Guardian Knights Talisman in the possession of Cade Yeager in exchange for the release two CIA operatives that he snatched up as hostages. Secretly, Morshower believes the TRF can use the Decepticons so they can get hold of the Talisman, and thus the Staff of Merlin, themselves.
 * The first Decepticon on the list is Mohawk, who the lawyers easily agree to release.
 * The second Decepticon is Dreadbot, who they initially refuse because he murdered nine humans in what was though to be a bank robbery, though they decided to release him as long as he was outfitted with a GPS tracker.
 * The third Decepticon is Nitro Zeus, who they release under the following condition: he has to stay within the county.
 * The fourth Decepticon is Berserker, though this turns out to be a step too far due to the 'Con's homicidal nature, thus making him uncontrollable for even Megatron. Therefore, Megatron is forced to select Onslaught, who needed high-level clearance to be released, instead.