[Zero can only imagine all of it. Albeit not to a great degree. Imagine, but not at all relate. There's no what he could.]
It's not the Kaname she would have ever expected, either. But this is why she was holding back, as you now realize.
[Although there are so many more things which he isn't going to - can't, won't - tell Haruka. Those things which only Yuuki can bring to the surface. He doesn't know he's long dead. He doesn't know that Juri gave her life for Yuuki to live in the sun and free of any burdens.]
I don't know every last detail. But he was tired. He set out on that path, and wouldn't let anyone stop him. Not even Yuuki, though she desperately tried.
[Although it reached a point where the hunters accepted it— they even aided him by preparing the furnace.]
He even attempted to have Isaya Shouto turn her into a human [again] so that she wouldn't have any memories of him.
[Something within Zero tenses the more he speaks on this matter.]
That man. . . Everything that went wrong in my life was because of him. All of it.
[It's only because it led him to Yuuki does Zero feel he wouldn't change things if he could do it all over again.]
But I know that's not the Kaname you remember, either.