They Fight Crime: Ronin of Time

He might be called the Lonely Man.
Or the Ronin of Time.
If anyone remembered him at all.

Once, there was a creature so wicked it tried to crash the universe. It used temporial paradoxes to try to force the universe to undo itself. It killed Hitler as a baby, and pulled Jesus off the cross. It gave Davinci a lobotomy and gave nuclear bomb secrets to the Japanese in 1927. The universe wobbled by the constant attacks on reality.

One man was in the right place, the right time, and had the right attitude to fight the monster. Using technology that no longer ever existed he pulled up his past and his future like big carrots out of the ground. He then rolled up all that he was into one present without past or future. A walking paradox, he could not longer be effected by changes to the the timestream. He couldn't even be tracked as he existed only in the forever flitting horizon of the present. With the ability to travel all of space with a thought the newly created Ronin hunted the creature and finally killed it. He then traveled to those who could span time to tell them how to repair the damage.

Since then the Ronin has traveled the universe doing what good he can. He's lonely though. One of the odder paradoxes of his new existence is that the universe recognizes his actions but conscious minds do not after he has left his presence. He could rescue someone from a fire and the minute he left the would forget how they were saved.
Only three beings remember the Ronin. The Master of Phoenixes who lives on the Island of the Moon will remember the Ronin no matter what incarnation he is existing in. The Galatic Historian will always remember since it is his purpose to remember what is, what will, and what was idly thought of on a Thursday afternoon. The Lost Love remembers, and the less said the better.

If for some reason you avoided death by some miraculous means but can't exactly remember how, perhaps you were saved by the Ronin of Time.