User is Fyodor Dostoevsky
A person feels the pain of his soulmate when soulmate causes it to himself.
Dazai didn't think about his soulmate's condition when he tried to hang himself or cut his hands in particularly difficult times. The only thing Dazai wanted from life was to escape from it, and he didn't need a soulmate. Hardly anyone would like someone like Dazai.
Who is his soulmate? Where does he live and where is he now? How does he feel the burden of Dazai through time and distance? Too many stupid questions.
Dazai didn't feel his soulmate's pain in response, only small, faint flashes of something that didn't look like physical injuries. The pain can be different, and the mental wounds are sometimes deeper and more sophisticated. For some reason, Dazai was disgusted that he might someday meet the person destined for him, who would see a bandaged misunderstanding, desperately wanting to wipe himself off the face of the earth.
Dazai has put himself in danger countless times in order to prove something to someone and forget that he can be someone's light and destiny. Nonsense.
And... Fyodor destroyed Dazai's plans, messed up his cards, confused Dazai with a single phrase thrown in Osamu's face: "We must be soulmates." Because it was obvious, but more so to Fyodor: Dazai was obsessed with hurting himself, even if he hated the pain of cuts, bruises and fractures. And it became clear that no one but Dazai could torture himself so much that Fyodor couldn't sleep for hours from these sensations.
"This is bullying. Why you?"
Dazai felt both relief and a heavy burden on his shoulders. Fyodor is not an innocent simpleton, and he don't look at Dazai with contempt. Fyodor is somewhat similar to Dazai, but is also a terrorist obsessed with his sick ideas, an enemy of this world. Yes, he is damn interesting, and Dazai is less dead than usual when he hears Fyodor's serene voice, thinking that his enemy is closer to him than everyone else on this planet.
But if this is indeed fate, then it is both wonderful and terrible. Dazai doesn't understand how he can now feel so miserable and happy at the same time.