Underdark:Defense
Tactical Tower Defense
Free · In-App Purchases · Designed for iPad. Not verified for macOS.
Defend the Flame from the dark! Level up, strategically place towers, and choose buffs to grow stronger. Keep the light alive!
Defend the Eternal Flame: Experience the thrill of defending the flame from hordes of dark forces that besiege it! Feel the exhilaration as you clear stages, with each victory more satisfying than the last.
One-Handed Gameplay: Enjoy easy-to-master controls, designed for one-handed play. Perfect for strategic fun anytime, anywhere.
Customize Your Defense Strategy: Select buffs and strategically place towers to forge your path of resistance. As you level up and choose your growth buffs, your defense becomes an impenetrable fortress.
Heroic Stand: Choose your guardians to stand against the night. Each hero brings unique abilities to the battlefield. Earn trophies, level up, and enhance your heroes to ensure the flame flickers on through the darkest nights!
more [Notice] Cloud Save Button Restored
Hello,
The 'Cloud Save' button that was temporarily disabled has now been fully restored.
You can use the Cloud Save feature normally again.
We sincerely apologize for any inconvenience and thank you for y
3.2.1 1 Jun
[UnderDark:Defense June Update]
- Reaper and Fat Shark heroes are newly revamped.
- Reaper’s minion system is improved.
- Fat Shark’s iron anchor ability is improved.
- Normal stages are expanded up to Stage 940.
- The Bingo event begins.
- Translation and item box related bugs are fixed.
- 1 additional support mercenary ability slot is added.
3.1.9 31 May
[UnderDark: Defense] May Update
- Balance improvements will be applied to Alien Spaceship and Joker characters.
- Alien Spaceship’s Black Hole and Laser abilities will be enhanced.
- Joker’s Card Stack and Surprise Box abilities will be improved.
- Auto option settings for items, mounts, pets, and relics will be added.
- Hero and tower stat calculation details will be improved.
- An issue with the oversized unlock icon in the Silkworm Moth Dungeon will be fixed.
3.1.8 21 May
[UnderDark: Defense] May Update
- A new hero, “Alien Spaceship,” has been added. (Equipped with Laser and Black Hole skills)
- The Joker hero has been revamped, improving attack mechanics and growth elements.
- Normal stages have been expanded up to 930, with new stages added.
- Events have been updated. (Board minigame begins / Bingo and Tower Pass end)
- Balance adjustments have been made to boomerang-type items.
- Some ranking translation errors have been fixed.
3.1.7 30 Apr
- Se corrigió un problema que mostraba el selector de cuentas de Google en cada inicio de sesión.
3.1.6 19 Apr
[Underdark: Defense] April 11 Update
- Guild capacity adjusted to 50 to match server limits and fix UI display issue
- Fixed an issue where weekly spending ranking currency changed abnormally
- Fixed an issue where Goblin Factory Tower was infinitely duplicated due to Imp Hero effect
- Fixed an issue where Sun Ring refresh option did not work properly
- Fixed an issue where buffs were skipped when refreshing after watching ads
3.1.5 10 Apr
This update from Apple will improve the functionality of this app. No new features are included.
[Underdark: Defense] April 1 Update
- Stages are expanded up to 920.
- The Season Pass will be updated.
- Living Tower growth missions are added.
- Living Tower heroes are buffed.
- The “Unexpected Companion Chicken” hero is buffed.
3.1.4 31 Mar
[Underdark: Defense] Update
- Added 4 new towers
- Added new ranking dungeon “Silkworm Moth”
- Added new limited tower pass
- Reduced difficulty of Co-op Dungeon 1
- Fixed an issue where the Buff Reset +1 option did not stack
3.1.3 22 Mar
[Underdark: Defense] March 14 Update
- New content Guild 4-player co-op dungeon added
- New items 2 helmets and 2 rings added
- Guest accounts are excluded from the Top 10 ranking
- Spending ranking closing time adjusted to every Sunday 23:50 (KST)
- In the spending ranking, guest accounts will start being counted after linking a Google or Apple account
3.1.2 14 Mar
[Underdark: Defense] March 13 Update
- New content Guild 4-player co-op dungeon added
- New items 2 helmets and 2 rings added
- Guest accounts are excluded from the Top 10 ranking
- Spending ranking closing time adjusted to every Sunday 23:50 (KST)
- In the spending ranking, guest accounts will start being counted after linking a Google or Apple account
3.1.1 12 Mar
Fixed an issue where the weekly ranking currency changed at the wrong time.
The weekly ranking currency has been changed back to Diamonds.
3.1.0 7 Mar
Fixed an issue with claiming Weekly Currency Ranking rewards.
3.0.9 5 Mar
[Underdark Defense] March 1 Update
- The Mysterious Armor hero will be remade.
- The Mischievous Devil hero will be remade.
- Stages will be expanded up to 910.
- A Weekly Spending Ranking system will be introduced.
- Co-op Mode stability will be improved.
3.0.8 28 Feb
[Update Details – February 2]
Bug Fixes & Improvements
- Fixed an issue in Daily Dungeon Multiplayer mode where some players could not press the entry button or the UI was not displayed correctly.
- Fixed an issue where the Daily Dungeon Multiplayer ranking UI was displayed incorrectly.
- Fixed an attack speed–related issue occurring in Daily Dungeon Multiplayer mode.
- Balance adjustment: Gamblewood has been nerfed.
- Gamblewood Lv.6 ability has been adjusted. (Max 2000% → 500%)
3.0.7 2 Feb
[Update Details – February 1]
Hero Improvements
- Hero Gamblewood has been revamped!
- Hero Thor has been strengthened!
New Dungeon and Special Notes
- Normal stages have been expanded up to Stage 900.
- 10 new stages have been added.
- A multiplayer mode has been added to the Daily Dungeon.
Events
- The Bingo Mini-Game begins on February 1 (KST).
- The 2026 Event ends on January 31 (KST).
- The Board Mini-Game ends on January 31 (KST).
Bug Fixes and Improvements
- Fixed an issue related to guild levels.
- Improvements have been made to pet summons.
3.0.6 31 Jan
[Update Details – January 1]
New Hero
- The Nine-Tailed Fox joins Underdark!
- Defeat enemies together with the charming Nine-Tailed Fox!
New Stages and Special Notes
- Normal stages have been expanded up to Stage 890.
- 10 new stages have been added.
Events
- The 2026 New Year Event begins on January 1 (KST).
- The Board Mini-Game begins on January 1 (KST).
- The Bingo Event ends on December 31 (KST).
Bug Fixes and Improvements
- Lava Golem optimization has been applied.
- Lava Golem’s Fireball damage and movement speed have been increased.
- A Curse Tower tutorial has been added to Stage 21.
3.0.4 31/12/2025
[Update Details]
Bug Fixes and Improvements
- The issue where the ranking dungeon disappears will be fixed.
3.0.3 10/12/2025
[Update Details]
Bug Fixes and Improvements
- The existing co-op dungeon will be added again.
- An issue where the in-game scrollbar range becomes narrow will be fixed.
- An issue where the Battery Tower was not affected by the Wind Boomerang will be fixed.
- An issue where obstacles were displayed abnormally in Zombie Penguin Village will be fixed.
3.0.2 02/12/2025
[Update Notes – December 1]
New Hero
- The Lava Golem joins the Underdark!
- Melt your enemies with powerful Meteors and Fireballs!
New Stage & Special Features
- A new stage will be added.
- A new co-op mode will be added.
Events
- The Board Game mini-event ends on November 30 (KST).
- The Halloween event ends on November 30 (KST).
- The Bingo event begins on December 1 (KST).
Bug Fixes & Improvements
- Fixed an issue where the “End of War” display appeared abnormally.
- Expanded the maximum item level.
- Added a support mercenary slot.
- Added a feature that allows faster growth selection.
3.0.1 30/11/2025
[Update Notes – November 1]
New Hero
- Succubus joins the Underdark!
- Defeat monsters through the alluring mist of the Succubus!
Hero Improvements
- Fat Shark’s level 3 ability has been enhanced.
- Plague Doctor’s level 12 ability has been enhanced.
New Stage & Features
- A new stage will be added.
- Account level cap expanded to 300.
- Daily Dungeon hero levels will now randomly vary between levels 1 and 12.
Events
- The Bingo Event ends on October 31 (KST)!
- The Board Event begins on November 1 (KST)!
- The Halloween Event begins on November 1 (KST)!
Bug Fixes & Improvements
- Fixed an issue where the game would close abnormally in certain dungeons.
- Fixed an issue where the account level increased abnormally in the level 241 range.
- Fixed an issue where Valkyrie’s support mercenary effect was not applied when auto-equipping weapons.
- The abilities of Guild Dungeon 1 Boss and Medusa Boss have been reduced.
- The item draw limit has been increased to 2000.
3.0.0 31/10/2025
Fixed an issue where Stage 851 could not be progressed
Fixed an issue where the Cheerful Pirate Shark skin could not attack
Corrected the display error in Battlefield of Doom
Fixed an issue where Anubis’s Mark was incorrectly displayed on certain units
2.9.9 04/10/2025
[Update – October 1]
New Hero
- Anubis joins the Underdark!
- Sweep through dungeons with the ancient hero Anubis!
New Pass
- 6 new Hero Passes will be added.
New Stage
- New stages will be added.
Event
- The Board Game mini-event will end on September 30 (KST).
- The Bingo Event will begin on October 1 (KST).
Bug Fixes and Improvements
- The Apocalypse Battlefield ranking will be reset.
- The Apocalypse Battlefield ranking calculation will change from cumulative damage to a point-based system.
- Fixed an issue where the Relic of Immunity in Guild Dungeon 1 would not deactivate.
- Fixed the shark appearance of the Cheerful Pirate skin.
- Fixed an issue where some pets were not being pushed back by heroes.
2.9.8 30/09/2025
[Underdark: Defense]
- Fixed an issue where the chat function was not working properly.
- Fixed an issue where the full immunity debuff in guild dungeons was not deactivated.
- Fixed an issue where heroes appeared abnormally while moving on top of the tower.
- Fixed an issue where heroes on top of the tower did not receive various buff effects.
2.9.7 08/09/2025
[Update Notes – September 1]
Bug Fixes and Improvements
- Fixed text error for Valkyrie support mercenary.
- Added sounds for Valkyrie and the new tower.
- The swords around Valkyrie now apply knockback effect to monsters.
- Fixed an issue where some character data was lost due to co-op mode.
2.9.6 01/09/2025
[Update Details – September 1]
New Hero
- New hero [Valkyrie] joins Underdark!
- Sweep through dungeons with Valkyrie, the hero of the battlefield!
New Tower
- [Mysterious One-Eyed Portal] has been added!
- Use the portal with mysterious power to play strategically!
Event Changes
- Bingo Event ends on August 31 (KST).
- 1st Anniversary Summer Event ends on August 31 (KST).
- Board Game Mini-Game starts on September 1 (KST).
- Board Game Mini-Game duration extended.
Bug Fixes & Improvements
- Rocket Tower optimization applied.
- Fixed an issue where heroes got stuck on towers and teleported.
- Fixed an issue where curses did not trigger in Abyss Hole Dungeon.
- Fixed an issue where Jangseung Totem and Paladin critical damage stacking was not applied.
- Normal stages expanded up to 850.
Character Balance Patch
- Siren: Blue Conch Tower crit damage 60% → 120%
- Siren: Conch Tower buff range increased
- Jolly Pirate: Bomb acquisition 6s → 3s
- Jolly Pirate: Hell Barrel chain explosion stacking improved
2.9.5 31/08/2025
[Notice] Cloud Save Button Restored
Hello,
The 'Cloud Save' button that was temporarily disabled has now been fully restored.
You can use the Cloud Save feature normally again.
We sincerely apologize for any inconvenience and thank you for y
more Version 3.2.1 1 Jun
Data Used to Track You The following data may be used to track you across apps and websites owned by other companies:
Location Identifiers Usage Data Data Not Linked to You The following data may be collected but it is not linked to your identity:
Location Identifiers Usage Data 