Please help me find an anime!

[llkeffll]

Can someone please, please, please help me find this anime! I have been searching on and off for literally years! I'm pretty sure I watched it on Adult Swim, but it was a long time ago. I think it's a movie. Honestly 50/50 on whether I dreamt the whole plot up at this point, though. But I'll try to summarize it as best I can. 

It begins with an image of a small hut in the middle of the woods in an older time of Japan, completely surrounded by either trees or maybe bamboo. The main character is immortal and is living in the hut, hiding from a secret-society type group that's run by a certain family who has been chasing him for generations in an attempt to learn the secret to his immortality and steal it for themselves. 

A woman stumbles on the hut while running from the secret society as well, and finds the main character. They run away together after a brief battle and, I think, eventually fall in love. They live their life on the run, but she ages while he does not. At some point, there is either one time jump or maybe two. But eventually we arrive to a future Japan, with the main character still running. All the land has been urbanized at this point, I think. 

He finally decides he needs to bring the fight to the family that's been chasing him. They are very wealthy and the final fight takes place in some kind of very tall tower, with maybe a glass some at the top? They fight, the winner may or may not be immediately known, but the final scene is the same as the first; a hut in the middle of nowhere surrounded by trees with smoke coming out the top... I believe the implication is that the futuristic society collapsed and life had returned to the older times again. Like a loop. 

Please, please, please help me. I have searched for this plot for so long, but cannot find anything about it! Does anyone out there know what this movie might be called? (If it actually exists )

[knight775042002]

I am looking for an anime. The anime start off in the olden time during samurai period then the second season start in the present time. The main character is a girl. She dress like a boy to take the brothers places. She travel with a samurai warrior. I believe they where looking for a rune or talisman. Please help thanks.