A manhwa (or manga) where the main antagonist is the protagonist's future self It's been bugging me for a few days now. I can't really remember a lot about it, but here are the things I kind of remember:   


I think it was Korean manhwa
The setting was old, martial arts was common.
I think the MC had amnesia.
He liked to climb trees (shown chapter 1, I think)
He time traveled back to a younger body (mind traveled)
His parents were suspicious of him for being "different than usual".
His parents were killed by thugs.
The female helper who was taking care of the main character got kidnapped and raped.
He later tracked the guy who attacked them and was about to kill him, when suddenly a girl stopped him from doing so. It turned out to be the helper; she was pregnant and in love with her captor. He left through the window.
The main character was scared of the main enemy (I think >.&lt;)
The enemy was wearing Sephiroth-like trench coat (tall)
Near the end, he found out that the enemy was him from the future (or alternate outcome of his choices)
They fought in the courtyard and both died I think, or just his future self.


I'm not sure if this is only 1 manga that I'm describing. It kinda feels 2.

I have tried googling this with what I think the genre/tags it would be under, but failed to find it :( 

I hope someone can help me stop this nagging in my head >.&lt;  Thank you for your time!
It's probably Threads of Time, a Korean manhwa.

It has been a few years since I read it, so my memory is fuzzy about the fine details, but it has enough similarities to be a match.

I definitely remember these details you wrote in the question:


  
  It was Korean manhwa
  Martial arts was common.
  He time traveled back to a younger body.
  His parents were suspicious of him for being "different than usual".
  The female helper who was taking care of the main character got kidnapped and raped.
  He later tracked the guy who attacked them and was about to kill him, when suddenly a girl stopped him from doing so. It turned out to be the helper; she was pregnant and in love with her captor. He left through the window
  The main character was scared of the main enemy.
  


The last 2 details (reproduced below) might be from a different manga if you're completely certain about it.


  
  Near the end, he found out that the enemy was him from the future (or alternate outcome of his choices)
  They fought in the courtyard and both died I think, or just his future self.
  


However, I think you might have gotten those details wrong, since the MC time traveled back into the brother of one of the villain's victim in order to untangle or sever the Threads of Time (Fate?). Near the end, he realized that the villain was his past self and he defeated him, but he also died soon after and returned to his present time. Though this time around, he is no longer tied down by fate/destiny because he broke the cycle.

Source: Years of reading manga.

Anyway, I hope this is the right one.