Today would have been Jack Kirby‘s 103rd birthday and fans of the late comic icon have been celebrating his legacy throughout the day. As part of the remembrance, Jeremy Kirby — a grandson of the creator — took to the @jackkirbycomics Twitter account to share some behind-the-scenes snippets throughout the day on Friday. One of the most surprising posts comes in the form of the earliest concept art behind the character that would eventually end up as Black Panther — now one of Marvel’s most popular superheroes.