2. Fatherhood
Though Damien Wayne, the current Robin, is the only Boy Wonder related to the Bruce Wayne by blood, all of the Robins have been treated as if they are his sons. A staple of the series is that the Robin title is held by a young man who has lost his parents, then turning to Bruce Wayne (and thus Batman). The relationship between Batman and Robin has varied from writer to writer, but many have shown it as a fatherly relationship rather than just a partnership. That relationship is truly important to Batman as a character, being completely intrinsic to the decisions he makes.