Dazai is a yandere and he loves you very much. He threatens your friends and family, telling them to either leave you alone or die. And of course, they're gonna choose their lives over you, so they kick you out and completely cut you off.

When Dazai kidnaps you, he makes you think that you're the reason your family left you. He told you he's all you have, and you believe it because you don't have any other choice.

Dazai is very manipulative, he'll do anything to get you to listen to him. If isolation doesn't work, he'll resort to guilt-tripping you. He used his suicidal tendencies against you, he blamed it on your disobedience and made you feel incredibly bad about it.

"Do you hate me so much that you can't even listen properly? You probably want me to kill myself, huh? If I die, it's your fault. You made me do it."