Two Worlds II property called Two Worlds II: Castle Defense.
The official site states, "Using foresight and skill, you must defend abandoned ruins, dark forests and winding catacombs against the onrushing Orcs. Ward off each attack with clever tactics and weaponry, defending Gandohar's throne in the Oswaroth fortress! Are you ready to break the high score, meeting the ultimate Castle Defense challenge against online opponents from around the world?"
The game has the gamer placing units to combat advancing orcs. There are six different kinds of units to buy and place in predesignated spots, and each one can be upgraded; for example, a fighter can upgrade to include a shield. Players can affect units even during combat, such as healing. All actions cost gold, however.
Players can check out the demo from the official site.