San Diego-based Sony Online Entertainment has purchased Carlsbad-based Sigil Games Online, the firm said late Tuesday. Sony said that it has completed a transaction to purchase key assets of Sigil. Financial terms of the deal were not disclosed. Sigil is the developer of Vanguard: Saga of Heroes, an online, massively multiplayer online game. Sony said that the majority of Sigil's team will join Sony Online Entertainment in its offices in San Diego, Seattle, Austin, Denver, Los Angeles, and Taiwan.