Board Thread:General Discussion/@comment-87.102.2.235-20160720090052/@comment-26397825-20170724014824

It is explained in the overview that the Guildmaster narrated (not the story Maze told you) that Jack demanded to know where the boy was from Brom but Brom held his silence, so Jack killed him for it. He attacked the village to get his hands on the bloodline that would allow him to get the sword of Aeons, but Scarlet wasn't enough and he demanded to know where the boy was. The point was he needed two people to get the Sword of Aeons - one to open the portal, the other to close it with the sword still on this side.

Twinblade took the girl who had been blinded by a sword across the face, Jack took Scarlet back to Bargate Prison, and the boy hid throughout the entire thing in the woods. I'm not sure what the reasoning for Jack not taking Theresa is, unless it's that she simply took after her father too much and didn't have the necessary power running through her veins - being only a Seer instead of a full Hero of Might, Skill and Will like the boy and Scarlet Robe.

But then that doesn't make much sense because you can kill your sister to close the portal and keep the sword for yourself. Maybe Jack is just sexist and simply didn't believe a young girl who hadn't shown any indication of being anything more than a Seer could ever be enough to close the portal after he'd gotten the sword.