Should he get killed, he's sent back to the dungeon heart, which loses some of its life energy. Deimos lives down in the dungeon alongside his minions, and you can move him around the map to kill enemies with his staff weapon or with spells, such as fireballs, poison arrows, and ice bombs.
Instead of using monsters, it's often much easier to do your own dirty work. By the time you've gathered enough soul energy to level up your monsters, hero levels have increased several times, making it incredibly difficult to keep up with them. This is fine in levels in which monsters are used more as bait than as dungeon defenders, but can be frustrating in levels in which you must fend off large groups of enemies. This requires a large amount of energy-more than you can gather from just a few heroes. To deal significant damage to heroes, you must increase your monsters' experience levels by using soul energy.
They often ignore passing heroes, and are barely strong enough to defeat them on their own. They just sit in their pentagram homes until an enemy happens to walk past. Unfortunately, killing heroes isn't as simple as sending your monsters after them, because you don't have direct control over any monsters you've built. The charred remains of your conquests can be seen on the map. When you've had enough, you can choose to kill the ungrateful adventurers and steal their gold or send them to a prison or torture chamber to extract more soul energy. Catering to the needs of mere mortals becomes incredibly tedious because the heroes never seem to be satisfied, often complaining about a lack of amenities such as libraries or armories, even if you've built several. If heroes crave gold, build a treasure chest if they crave knowledge, build a library or if they're masochists, create more monsters. To keep that soul energy flowing, you need to cater to each hero's need. You need soul energy to build decorative items and other structures called gimmicks, which in turn increases your prestige level, unlocking new missions that allow you to progress. Heroes carry a certain amount of soul energy with them, which increases as they find interesting things to look at, fight with, or learn from as they explore your dungeon. Rather than ask you to immediately kill them, Dungeons puts a new spin on things by asking you to look after them before you indulge your sadistic side. They run around your dungeon calling out for "more experience!" and threatening to destroy your dungeon heart, which can end the game. Your main objective is to lure enemies called heroes into your dungeon. You have to build a thriving dungeon in real time, filling it with monsters, such as mutant frogs, flying snakes, and rabid rats traps, such as floor spikes, swinging stones, and arrows and decorative items, like skulls and statues. The basic gameplay is ripped wholesale from Dungeon Keeper. It's your job to guide him back to power by rebuilding his empire and exacting revenge on his ex-girlfriend. Instead, she decides to steal Deimos' throne and cast him into exile at the top of the dungeon. He's having relationship troubles with his demonic girlfriend Calypso, and sadly, not even a bunch of flowers and a back rub is enough to win her back.
Most of the humor comes at the beginning of the game, where a silly plot introduces you to a dungeon master known as Deimos.