[Yandere + imprisonment + forced love + devoted to each other + no do-gooder heroine + happy ending]
[World One: When Jiang Nian first met Qi Yun, he was still the elegant young marquis. But when she discussed marriage with another man, Qi Yun went mad, claiming her and imprisoning her. It was love at first sight in the first world.]
[World Two: Jiang Nian was Qi Yun's master, and could only watch helplessly as he fell into darkness. After she severed their master-disciple bond, Qi Yun went mad and imprisoned her.]
[World Three: Jiang Nian transmigrated into a story about a fake heiress as the vicious supporting character. She framed the heroine and did every kind of evil, until she was driven from her home and mocked by everyone. She never expected her junior schoolmate to take her home and lock her up.]
This book is really good. The male protagonist is so crazy. I love it so much.