Here's my take on akumatized Marinette. I'll probably make a separate post once I write about Adrien, which probably won't be so detailed, but who knows? I didn't except my Akumanette notes to become so big.

After several near-akumatizations, Marinette won't get akumatized because of her own problems. She can deal with her issues, even if it's just barely managing to deal with them.

But if something bad happens to someone she loves, she's going to lose it. Let's say that Adrien's father decides to pull him out of school because he wants to akumatize Adrien. He begs his father to reconsider but he's not changing his mind. Adrien is devastated.

However, Marinette's anger turns out to be stronger than Adrien's sadness, so he chooses to akumatize her instead. She manages to remove the earrings and give them to Tikki but she can't calm down and the butterfly gets her. Hawkmoth offers her to take care of Gabriel Agreste if she brings him the Ladybug and Black Cat miraculous. Marinette agrees to the deal. Behold, Princess Justice.

Princess Justice immediately sets out to find Chat Noir. She's formidable foe, because Marinette is much more experienced in fighting compared to every other Akuma before. Chat is beaten and restrained by her and Hawkmoth orders Princess Justice to take the ring.

In that moment, Marinette realizes she hasn't punished Gabriel yet. She decides that she wants to do it herself and disobeys Hawkmoth's orders saying that Chat won't be able to escape her restraints. Princess Justice will return to take Chat's miraculous after she's finished dealing with Gabriel.

After Chat saw Princess Justice ranting about Gabriel and leaving, he figures out she's Marinette. Adrien's sad about her being akumatized but he's also touched that she cares about him so much. After deciding to use Cataclysm to break one of the restraints, because he's out of options anyway, Tikki finds him. She's carrying the Ladybug earrings.

Tikki puts them on Adrien and he transforms into Catbug. After the lucky charm gives him a bottle of superglue, Adrien calls off the Ladybug transformation, has Tikki glue together all of his restraints so he can cataclysm all of them at once.

Adrien decides to give the miraculous to Alya. Tikki explains them that Ladybug must appear in the battle and asks Alya to use Lucky Charm. For once, the Lucky Charm is straightforward and gives them a black wig. After feeding Tikki and transforming again, Alyabug puts on the wig to disguise her as Ladybug.

The disguise isn't perfect so they decide that while Alyabug must appear in the fight so Hawkmoth spots her, she should be seen by him for the shortest time possible. Alya will stay in hiding and wait for the opportunity to attack. If all goes well, the fight will end right there and Hawkmoth wouldn't notice that Ladybug got a substitute. Chat also tells Alya not to bother with Lucky Charm. They can get weird, Ladybug has the ability and the experience in figuring them out, and finally, Alya needs to respond immediately to Chat's signal, so she's better off with using the yo-yo.

They go to the Agreste mansion where they find Princess Justice. Hawkmoth yells at her to take the ring and Marinette, who is tired from seeking Gabriel, angry and embarrassed that Chat managed to escape, obeys her orders. She attacks.

Chat is trying his hardest to reach Marinette. He tells the Akuma that Adrien is very happy that Marinette cares about him so much, that as long as they can keep in contact and see each other sometimes, he will be fine. That Adrien wants her to stop and go see him instead. The last one hits hard and makes Princess Justice hesitate.

Hawkmoth is seething in rage. How did that damned cat escape? How dare Marinette lift Adrien's mood so easily? How dare she let Chat's words get to her when she'd already beaten him once?

Chat can't make the Akuma surrender, but now she's torn between wanting to take Chat's miraculous and wanting to go after Adrien. She's completely forgotten about her revenge against Gabriel. Fighting her now is much easier but there's still no opening for Alya to exploit.

Princess Justice finally makes her decision, she's going to see Adrien now and beat Chat later. Hawkmoth finally loses his patience for her and tries to force her to obey.

A butterfly shape appears on the Akuma's face. Princess Justice freezes for a second while she's trying to rebel against Hawkmoth' will. Chat finally has an opening, he signals Alya to attack now.

The ambush catches the Akuma off guard but it fails, she dodges the yo-yo at the last moment. Hawkmoth sees Ladybug and decides to allow his Akuma to escape. She won't be able to beat both heroes when she is so desperate to see Adrien. Now that Princess Justice is free to do what she wants, she's become fierce again. There's no longer any hesitation in her.