>>2334303>Why is this guy always abused in fanart?kek.
Aldnoah.Zero takes places in an alternate universe where the Apollo missions discovered a stargate to Mars, and then discovered a bunch of alien technology on Mars. Using alien technology, Earth colonizes Mars -- but the Martians, using their alien technology, declare independence and become Earth-hating (xenophobic?) chuuni feudal militaristic pseudo-Prussian nutjobs.
Slaine is from Earth, but his dad gets invited to study the alien ruins on Mars, so Slaine moves to Mars. But then Slaine's dad dies, and Slaine gets shunted off to live as the ward/adjutant/servant of a particularly especially racist and chuuni Martian who verbally abuses him and beats him with a cane. From this point on, nothing good ever happens to Slaine without something worse accompanying it. He finds the girl he wants to protect, he gets shot down and tortured. He finds the girl he wants to protect, she gets shot in the head. The girl he wants to protect comes out of a coma, she rejects him because he's spent the last few years waging an interplanetary war to keep her safe. He tries to commit sudoku, a one-eyed autist locks him in the basement and force-feeds him eggs. He's a very good, earnest, and daring boy, but every time he tries to do good, it rebounds and makes his life worse.
He's a perfect storm of cute character design, cute voice, abuse, sub-human treatment and general denigration, military kink, uniform kink, torture kink, rival shipping, master-servant shipping, hope and despair, just enough spirit to keep going through it all ... he's truly a miracle.