Pretty sure I mtled it, doesn't have many arcs, mostly a one time read so I forgot to bookmark. I hope someone can help ^^ ABO Arc MC transmigrated into an omega from a prestigious family. He was from the main branch. The alpha king liked orihost but idk MC refused or smtn so he arranged MC to be married to his elder brother (ML). Years ago the elder brother got injured in the battlefield and as a result he can only stay in juvenile form (can't have xxx or mark MC) thus losing right to inherit. Even though he couldn't be an adult, eldest prince still battled on the frontline fighting against rebels. In the Orihost lifetime, he didn't like his husband. Was impressed by the rebel leader (name started with R) and revealed husband's info, military secrets etc to the rebels. At the end eldest prince died, rebels took over the country and monarchy was changed to something on the lines of presedential rule. Orihost regretted his actions after husband's death. After MC transmigrated, he was warm towards the eldest prince (ML), and followed him to his place. The king married two omegas, one of them was from MC's sidebranch. MC goes into heat in the Prince's mansion and the rebel leader guy breaks in and helps him out with hand. MC figures out that eldest prince hubby = rebel leader. He can transform between adult & juvenile forms but it is a secret. Then MC & ML plot together. The rebels capture MC's bro who was a soldier and demand MC as captive to spare bro's life. MC surrenders. Bro is led to believe that MC truly loves rebel leader and says he'll assist in the rebellion. Then ML, as eldest prince breaks into rebel camp and rescues MC. Meanwhile the omega from MC's family who married the king died under king's torture. The king finds lame reasons to execute the eldest prince, accusing him of treason. MC asks to be punished together. They get send to a special kind of prison. ML escapes via underground. Rebels bomb the place & everyone believes that eldest prince dies. ML saves the MC as the rebel leader. Later he successfully takes over the capital, marries MC & becomes 1st president. Another arc - Overhead ML is the leader of a dance troupe who injured his legs & can't dance. ML plans to select a successor via audition. In the original plotline MLs character was a canon fodder who was used as stepping stone by Female protagonist. She first joins ML's troupe then switches to Male protagonists troupe. After MC transmigrates, he auditions for MLs troupe. ML selects him & Fem protag and trains them both. Whoever wins a competition will become the successor. The Male protag watches MC's dance & gets interested in him. He blackmails MC using MC& ML's pics and calls MC to his room. He wants MC to sleep with him but MC uses hypnosis on him. So he believes he slept with MC but j reality he slept with another female contestant (sort of green tea b**ch). Male protag tells ML that he blackmailed MC & slept with him. ML propses to MC. He says something on the lines of " i never liked things which are touched by others but when it comes to you it doesn't even matter" & proposes to get married abroad. MC tells him that he just used Hypnosis, he had also shot male protag & gtb participant. Fem protag also falls in love with MC. After MC rejects her, she switches to Male protags troupe. Ending is MC & ML getting happily married. Male protagonist falls in love with female protag & they get married but the relationship stays strictly platonic as fem protag is with him because of his status & doesn't really love him. Also ML gets cured & resumes dancing. While Fprotag uses Mprotags identity to perform abroad, foreigners visit China to watch MC & ML's performance.
https://www.novelupdates.com/series/this-cannon-fodder-is-covered-by-me/ Any chance it would be this novel? Only read the translated chapters which were not the arcs mentioned but still thinks the main theme matched: where ML were supposed to be cannon fodders.