Editing Siryn (section)

===Early life===
While Sean Cassidy was working on a deep undercover mission for [[Interpol]], his wife Maeve gave birth to their daughter, Theresa, at Cassidy Keep, County Mayo, Ireland. Maeve later dies in an [[Irish Republican Army|IRA]] bombing, and with no means to contact Sean, his cousin [[Black Tom Cassidy|Tom]] takes care of Theresa. When Sean returns and learns of his wife's death, he is devastated. Before Tom can tell him about Theresa, Sean lashes out at Tom with his sonic scream for not having taken better care of Maeve. As Sean flies away in anger, Tom falls into a chasm and breaks his leg, leaving him with a limp. Tom swears to make Sean pay and vows to never tell him about his daughter, and raises her himself.<ref>''X-Force'' (vol. 1) #31 Marvel Comics.</ref>

Tom (now known as Black Tom) trains Theresa as his apprentice in his criminal activities. As a young teen, she accompanies him and his then-partner, the [[Juggernaut (character)|Juggernaut]], to [[San Francisco, California|San Francisco]]. She takes the name Siryn, aids them in a [[vibranium]] theft, and battles the original [[Spider-Woman (Jessica Drew)|Spider-Woman]].<ref>''Spider-Woman'' #37. [[Marvel Comics]].</ref> Due to her inexperience, she performs poorly in battle and is defeated by Spider-Woman again during Black Tom's temporary capture. Initially believing her to be seriously hurt, Black Tom resolves to break all association with her so that she will not be exposed to further danger. While in custody, he absolves Theresa of all responsibility for her crimes,<ref>''Spider-Woman'' #38 Marvel Comics.</ref> and writes a letter to Sean explaining who she is. The X-Men bring Theresa back to their headquarters, where she is joyfully reunited with her father.<ref>[[Claremont, Chris]]. ''Uncanny X-Men'' #148 Marvel Comics.</ref>