Sol Invictus

I read this manga a few years ago so my memory is rather hazy but it centers around time travel and mostly takes place in a sort of post-apocalyptic future where people have special powers. Very vague, I know. Let's see if I can do better: what I remember is that the protagonist is a young man and he's on a journey and meets this scientist and they start of bickering but then they fall in love but then there's this other girl from a terrorist organization and she happens to cause this bomb to go off so the scientist chooses to do the best she can to contain the fallout from the bomb and ends up sacrificing her life while the main character watches from behind a shield. what happens later is that there's a time skip and the protagonist appears to be working for the organization he once opposed but actually he was brainwashed by his friends (who are still fighting against said organization) and they later undo the brainwashing once they feel they're ready to fight the organization again (apparently the protagonist got stronger as well). somehow in all of this there's also time travelling going on and something about John F. Kennedy. yeah this all sounds super confusing but if you've read the manga you'll know what I'm talking about.

incidentally the art is great. 

thanks for the help.