This article is not suitable for amatures under 18. YOU HAVE BEEN WARNED!

The Trials of the Monster Labyrinth Series (モンスター迷宮シリーズのトライアル Monsutā meikyū shirīzu no toraiaru), or Monster Dungeon Series overseas, is an eroge role-playing game exclusive for PCs (obviously).


The Monster Dungeon Series is set in a mysterious labyrinth where a party made up entirely of female characters have to escape in order to make it back to the real world. All of the enemies of the games are anthropomorphic, monsterous/demonic beasts, hence the series' name. It's similar to the MegaTen series where you navigate in a 3D maze set in first-person perspective, and once you encounter a monster you have 3 choices: Engage, Talk, and Escape.

  • Engage: If you select Engage, you will begin having sexual activities with said monster(s). As you keep up the sexual activities, you lose Energy, which is the HP of the series. The Cum gauge is just for visual effect, but it will make the opponent more likely to cum also if his penis is inside the female's vagina. But you must lose it wisely since it will deplete the character's Energy if it's triggered. If you run out of Energy, the next party member takes her place. If the entire party runs out of Energy, you become sex slaves and it's game over. If it goes vice versa, you win!
  • Talk: You have a chance to skip this encounter by selecting this option. If the monster is more "civilized", the following things are more likely to work: Massage, Calm him down, Negotiate, and Bribe. If the monster is more feral (e.g., a dragon), the following other things are more likely to work: Soothe it and Pressure points.
  • Flee: You also have a chance to escape from the encounter by choosing this option, but be warned: there's a chance more enemies will appear in an encounter next time.

There are also multiple endings in this series:

  • Bad Ending: If you lose to a boss, your party will become sex slaves and the game ends regardless, but you have the option to continue from where you left off (it won't trigger the boss battle), retry the boss level sex battle, or restart the game from the beginning!
  • Normal Ending: Happens if you complete the game without ever obtaining all Magical Repels.
  • Good Ending: Happens if you complete the game with all the Magical Repels obtained.
  • Hidden Ending: Happens if you have defeated all of the bosses with all the party members used in each encounter and you choose to become sex slaves when you defeat the final boss.

Trials of the Monster Labyrinth Gaiden / Monster Invasion

Basically the same game in different settings in each one. You get to play as the enemy monsters from the mainstream series, meaning you will be raping the female humans in the real world. Your goal is to find and rape all of the females in the location by morning or evening, depending on the games. The endings are also altered to fit the nature of the monsters:

  • Bad Ending: If you have not raped at least half of all the females in the location under the time limit, it's game over.
  • Normal Ending: Happens if you have raped at least half of all the females in the location.
  • Good Ending: Happens if you have raped all of the females in the location.
  • Best Ending: Happoens if each party member has taken a turn with each females and they become sex slaves.


  • Energy: The HP of the series.
  • Cum: The max amount you can ejaculate per encounter.
  • Strength: Determines how much you will gradually deplete the opponent's Energy and how much you will gradually increase the opponent's Pleasure gauge during sexual activities.
  • Endurance: Determines how much lesser your Energy and Pleasure gauge will decrease and increase, respectively.
  • Cum Amount: How much Cum you will jizz and Energy you will lose if your Pleasure gauge reaches full amount.
  • Cum Time: How long you will be cumming.
  • Critical: Has a variety of effects.

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.