This is how Celestia turns to Makuta for help goes in The NEXO Pony Knights.
[Celestia arrives in the Shadow Realm and flies towards Makuta's castle. She lands and knocks on the door]
Princess Celestia: It's me Princess Celestia. I demand to see Makuta.
[Makuta opens the door]
Makuta: Ah, Celestia. Please come in.
[She comes in and they sit near a fireplace]
Princess Celestia: I need your help Makuta.
Princess Celestia: My sun is loosing it's light.
Makuta: How come?
Princess Celestia: You see, my subjects don't admire it like they used to and I realized that you were the only one who could help.
Makuta: Why, yes. Anything for you.
Princess Celestia: Really?
[Makuta leads her to storage chamber]
Princess Celestia: A storage chamber?
Makuta: In here, you will find what you need.
Princess Celestia: To keep my sun shining?
Princess Celestia: Thank you.
Makuta: You are most welcome.
[Celestia levitates a fiery helmet out of the storage chamber]
Princess Celestia: What's this?
Makuta: It is what you have been looking for.
Princess Celestia: Are you sure?
[She goes to put it on then stops]
Princess Celestia: Are you sure about this?
Makuta: Just put it on.
[Celestia does so and she turns into her evil alter-ego Daybreaker]
Daybreaker: [evil laugh]
Makuta: Yes. The sidekick I was looking for has been born.
Daybreaker: Indeed I have.
Makuta: You predicted that Celestia would turn into you and you were right.
Daybreaker: And through my reign, daytime lasts forever!
Makuta: And with my power and your magic, we could rule this land with you as my queen.
Daybreaker: I would love that.
Makuta: Very well.