I'm trying to track down a graphic novel I read about 7 or so years ago. The protagonist was an immortal watcher who kind of nudged the course of history at several points in time and had a limited ability to rewind time. He also could teleport to and from his home which was this tower-like library with floor to ceiling bookcases chronicling his observations.
I remember burned Cortez's ships in a flashback but the central conflict is him trying to stop a grey goo incident with a nanite experiment escaping a lab.
It was mostly narrated by an unseen villain who was foiling his efforts to guide history in a productive way.
I seem to remember it's maybe ten years old, I think it was relatively new when I read it.
I also seem to vaguely remember Neil Gaiman may have been involved? Or maybe just wrote a little blurb praising it? That's the detail I'm fuzziest on, I may be completely misremembering that part.