Summoning Circles are pentagrams printed on the pathway outside of Vez'nan's tower.
In each of the mid to late waves, Vez'nan will summon Demon reinforcements straight from the netherworld in periodic bids to overwhelm your defenses with increasingly large numbers. The uppermost Circle will be the only one Deomons will come from starting at Wave 6, but the middle one will activate at Wave 8 and then lowest one will activate at Wave 12.
Luckily, all Demons that come from these Circles give bounty.
- Demon Spawn
- Demon Hound