Silas Sinister is a warlock who is the head of Sinister, Inc., father of the Sinister Sisters, and leader of The Dominion. He and his group targeted a box that contained the key to dominate Halloweentown. He and the other Dominion members are stripped of their magic powers and arrested by Professor Periwinkle (who was working for an Anti-Domion movement) for thier acts of treason.

Silas Sinister is portrayed by Keone Young.