Dungeons 3
60 Achievements
Prison Break
Free Thalya in less than 45 minutes in the “Light and Shadow” mission.
10.2%
How to unlock the Prison Break achievement in Dungeons 3 - Definitive Guide
In order to unlock and activate the southern dungeon entrance, you need to discover it first, you can do so by digging straight south in your dungeon until you hit the spider nest right next to the entrance, OR you can explore the overworld and have it unlocked that way.
First of all, you need to focus on your defenses in the dungeon, you don't want those heroes grinding down your dungeon heart's health while you're on an expedition. Connect all the entrances with pathways to have an easier time controlling the heroes in your dungeon and then lead them onto a labyrinth trip through your dungeon. That will give you time enough to use a portal spell and send your creatures back into the dungeon again to repel them if you need to.
I focused on expanding the graveyard for the extra undead I would gain from the invading heroes and then I added more room for an arcanum and space for more demons, you start with the undead titan, the grave golem, and he is a great tank and can take on the aggro from the enemies so he is a good combo with fire-spitting demons.
Go out the southern entrance once you're confident enough to take on the path and then kill all of the enemies until you reach the city, here you will have 2 gates you need to destroy, destroy the first gate along with the arrow towers and then take out the first group of defending heroes inside, then ignore everything else and attack the 2nd gate and Immediately attack Thanos.
Ignore everything else, attack Thanos, and don't mind the cannon towers nor the heroes attacking you from behind. Once you attack Thanos he will have a dialogue and then you're done, Thalia is free.
You will lose all your creatures when Thanos attacks but the achievement will be unlocked now unless you were too slow. (Reload an earlier save or start over in the worst case.)
If done right you can also guide Thalya near your dungeon entrance or your first island of evil and get all 3 achievements unlocked in one go, but it can be a bit tedious since Thalya will nag at you until you get her back.
Done in the "Light and Shadow" level. Not difficult as the defences aren't that strong. Once you reach Thalya, she's considered "freed". If you reach her in under 45 minutes, the trophy will pop.
A 10-creature army with the Grave Golem is sufficient to advance and destroy every Hero camp you come across, as well as capture every Island of Good. Somewhere at the 35-40 minute mark you can begin attacking the main castle area. There is no mini-boss battle, only standard units and castle towers, even though Tanos is standing there with Thalya. Since the Grave Golem is very tough, focus on support units and build up the Demonic research tree. Combined with Meteor Shower and Demon Strength, you'll easily overwhelm the small groups of Heroes scattered about the level.
Note that if you blitz through the map and destroy the Hero camps you'll not be able to get 100 Heroes killed by the time you free Thalya, thereby voiding I need a hero!. If you want to get both trophies together, keep the Hero camps alive. This will slightly complicate matters as you now need to deal with attacking the surface and dealing with invasions but it is doable. It's easier to make a manual save when you begin your rescue, get Prison Break done, then reload for I need a hero!