The Dark Tower

Enemies killed on the stage rise again from the graveyard 0.5 seconds after they die and walk onto the nearest path. An enemy with up to 299 maximum health returns as a Skeleton, a tougher one as a Skeleton Knight, and both give gold when killed. Bosses, Skeletons, Skeleton Knights, Demon Imps, Demon Hounds, Gargoyles, Rocket Riders, Giant Spiders, Spider Matriarchs, Worgs and Wulfs do not rise.

Rain of Fire can be cast on the graveyard even though it lies off the path.

In the Campaign, Vez'nan watches the battle from his tower while the waves run and cannot be attacked there. From wave 6 he summons demons through three portals, and from wave 9 he also traps towers.

Each portal cast opens the portals active for the current wave, and every open portal releases one random group of demons, one per second. The first portal releases 4 to 7 Demon Spawns (50%), 3 Demon Hounds (30%) or 5 Demon Spawns and a Demon Lord (20%); the second 2 to 5 Demon Spawns (50%), 2 Demon Hounds (30%) or 3 Demon Spawns (20%); the third, closest to the exit, always releases 3 Demon Spawns.

Vez'nan casts portals in waves 6 to 15. Wave 6: the first portal, up to 3 times every 15 seconds. Wave 7: the first, up to 2 times every 10 seconds. Wave 8: the second, up to 3 times every 20 seconds. Wave 9: the first, up to 3 times every 15 seconds. Wave 10: the first and second, up to 3 times every 20 seconds. Waves 11 and 12: the first and second, up to 3 times every 15 seconds. Wave 13: the third, up to 3 times every 15 seconds. Waves 14 and 15: all three, up to 3 times every 15 seconds.

From wave 9 Vez'nan traps several towers at once, and a trapped tower stops working. Clicking a trapped tower 3 times within 4 seconds frees it; otherwise it stays trapped for 6 more seconds. He casts it every 13 seconds in waves 9 and 10 (2 and 3 towers), every 14 seconds in waves 11 and 12 (4 and 5 towers), every 16 seconds in waves 13 and 14 (6 and 7 towers) and every 18 seconds in wave 15 (8 towers).

When the last wave is cleared, Vez'nan leaves the tower, appears at the start of the path and walks toward the exit, fighting soldiers in his way. He has 6,666 health on Normal (5,333 on Casual, 7,999 on Veteran), his attack deals 666 to 999 physical damage in an area every 2 seconds, and reaching the exit costs 20 lives. He keeps casting portals every 10 seconds (up to 40 times, all three portals) and tower traps every 18 seconds (8 towers).

When Vez'nan's health runs out he turns into a demon with full health again, moves faster and switches to a fire attack that strikes 8 times per use, each hit dealing 666 to 999 physical damage in an area. Killing the demon kills every enemy left on the field, and the Campaign ending plays.