Theodore Ostergard was born in 1878 to Esther and Victor Ostergard. Given plenty of toys and games, he became a spoiled child. Always striving to win also caused him to be a terrible loser. In May of 1890, his temperament reached a fever pitch where, in the matter of three days, he had killed the family butler, his mother, and then his father brutally (which he disguised as accidents) out of a jealous rage. When he and his friends gathered to trick-or-treat on Halloween night, 1891, he donned a cat-like mask and a top hat with a playing card in its band as part of his Halloween costume which became the signature parts of his outfit as "The Gambler".
After the gruesome events of that night he and his friends were adopted by Baxter Anderson (now under the control of Ruth). For a time he ran The House of Wonders and Gambling in town. It is unknown if the building is still running today as we only see it briefly in a photo in Forgotten Hill: First Steps but not as a playable location in any of the games. At some point after Nathan formally reopened the Puppet Theater, he decided to take up residence there. Now he gambles with anyone who enters, willing to indulge him in his games. Just remember, the house always wins...