Gotham will get a new pair of villainous siblings for season 2. Deadline reports that James Frain (True Blood, Orphan Black, True Detective) has been cast as Theo Galavan, brother of Tabitha Galavan, AKA Tigress. That character has not actually been cast yet, but the duo are expected to cause plenty of trouble for Jim Gordon when they arrive in the already crime-ravaged city. From Deadline's description it sounds like the Galavans will start out under heroic pretences.
"Galavan is the savior the city has been waiting for — he is sexy, heroic, and lovingly devoted to his sister Tabitha. But behind Galavan’s altruism is a centuries-old vendetta. Galavan and Tabitha (aka Tigress) will take chaos and violence to a new level in order to bleed Gotham. Their plan will lead to the creation of new villains… and the destruction of others."
Tigress has never gone by Tabitha Galavan in the comics, and as far as I know never had a brother - so this will likely be a complete reinvention of the character. Could Theo turn out to be another established DC villain perhaps? Speculate away in the usual place.