Yu Yu Hakusho1992

Koenma:
[thinking] If only I could rearrange the gears turning in your head! I don't want to use this on you! Please, return to the Sensui you were! [in flashback] If there has ever been a human destined to be Spirit Detective, it was you. You were born with incredible powers, and an obsession for making things right and just. It was my fault; I was too eager to close the case. How could I not have known how you would react, when you saw the darkest vices of man? When you realized that your life's work of protecting humans from demons was not a crusade of pure justice, but a study in gray?

Shinobu Sensui:
[in flashback] It is a war waged against evil, yet the evil is within. How else can I justify what I've done, but to continue? Then shouldn't all humans die?

Koenma:
But there has never been a light that did not cast a shadow. Darkness, by its nature, must always be entwined with good. I must take the burden for what you are now. I exposed you to that truth your idealistic mind can't understand. So, if you continue this battle for unearthly principles - if that's what you decide - then I will go with you. I'll trap myself in the net with you, share the pain of being trapped without movement for eternity. It's the least I can do. [aloud] Please, Shinobu, come around!