“More than what meets the eye” [Mysterious & Secretive protagonists]

A recommendation list for series featuring mysterious protagonists - Characters, who though are a main lead, we don’t know much at all about, with an overall air of secrecy surrounding them. It seems that perhaps there might me more to them than what meets the eye…

Not knowing their real names, their real identities, their history, their true goals, their motivations, etc, are all common of points of interest in most of these protagonists.
Some of these stories may center solely on said mysterious protagonist, or feature one who is paired with less-secretive comrades

[ The list may include implied spoilers for certain series. It’s quite obvious for majority of them. But just in case for certain series on here ]