(A/N: Requested by ZetaRaiser, and it's actually Reincarnation of Megatron (2005-2018 IDW Transformers comics continuity) Male Reader X Yandere Loving Azur Lane/Girls' Frontline/NIKKE/Punishing Grey Raven Harem.)
(Long after his execution, Megatron had reincarnated in the body of a young gray haired boy known only as Y/N, an ordinary boy who never attended a certain school, but once he reached 18, he regains his memories as Megatron. Even though he never attended Union Academy, he saw the injustice they commit, like faunus slavery, rape, powerless and innocent people being murdered, etc. This got him disgusted.)
Y/N: Such injustices. Reminds me of what Cybertron used to be...
(Then Y/N started uniting many people who were oppressed by Union. Among them are the shipgirls, T-Dolls, female soldiers and cyborg soldiers who had enough of Union constantly trying to put their hands on their technology and use them for military purposes. Once they met, Y/N, they knew something.)
Lucia: He's so... handsome...
Yuni: I can't wait to have my way with him soon.
AK-15: He's just my type of man.
Enterprise: We found our destined one!
(Then Y/N decides to reveal his true form, which is Megatron.)
AN-94: (shocked) Wow.
Nihilister: What are you anyway, stud?
Y/N: I am Megatron, and the atrocities the Union committed for too lone are no different that what used to happen in Cybertron before I became a leader of a faction known as the Decepticons.
Nanami: Then we are in the same boat. They have been constantly trying to get their hands on each of our technologies and use them for military purposes.
Belfast: And now that we're gathered here, let's join forces together against the Union.
Y/N: And under my leadership, we can start a revolution!
(Timeskip)
(The fight against Union Academy was easier than anyone would think. Megatron uses his vast power to finish both Union Headmasters and Star Students while the girls sadistically killed both boys who tried to flirt with them and girls who swore to make Y/N as their slave. As they won, Y/N dusts himself off.)
Y/N: I have millions of years of experience leading people in my previous life. So your defeat was not impressive at all.
(Then they girls surround Y/N (in his Megatron form) and hug him. Y/N then made his next step: destroy all of the League of Darkness, and anyone associated with Union, something he easily accomplished. Now he not only guided humanity for true freedom and peace, but he also got an harem of yanderes who love him unconditionally.)