Following Aaron's death while stopping Menniker from launching a nuclear missile, Jordan approached his grieving father and asked if he could be trained as a Guardian too in order to take up his brother's place. Rembrandt agreed, but trained Jordan in a different fashion than any previous Guardian. By keeping certain information — including the continued existence of previous Guardians — secret from Jordan, Rembrandt taught his son to gain responsibility gradually, eventually leaving him alone to learn self-reliance in a tradition that continued on to Jordan's son Mathias all the way down to Knuckles, though the Brotherhood of that time were uneasy about this change in tradtion. (KtE: #25)
Generations later, Jordan appeared to the deceased Knuckles along with other deceased Brotherhood members at the youngest Guardian's funeral. (StH: #121)
Jordan was the second Guardian with a unique marking on his forehead. The first was his grandfather Harlan, and those that followed include his son Mathias and great-great-great-grandson Sojourner, though the latter has a metal plate there instead of a natural marking.
A red Echidna, Jordan wore a blue vest, white gloves and grey boots. Jordan featured a unique marking on his forhead, a trait he shared with his grandfather Harlan and son Mathias. In the afterlife, Jordan's marking on his forehead looked more like a metal plate similar to that Sojourner. It isn't explained wether his marking was replaced by a metal plate at some point during his life, or if it was simply an artistic error.