Fathom Prelude and Fathom Beginnings were two one-shot stories from 2005 that gave glimpses into Aspen's past.
Fathom Prelude showed Aspen's teenage life and her journey with the USA Olympic Swimming team. The story sheds some light on why she was stripped of her gold medal and includes a possible appearance by the Unknown.
Fathom Beginnings shows Aspen's first appearance on the cruise ship Paradise. More clues are given as to the identity of the Unknown and the reasons for his physical state.
Read more about this topic: Fathom (comics), Fathom (2003–present)