Underdark Defense is a dark, atmospheric tower defense game that feels like a mix of 'Survivor' style progression and traditional defense mechanics. Your goal is to protect the Eternal Flame from waves of encroaching darkness. The strategic depth comes from how you place your towers and, more importantly, which buffs you choose as you level up during a match.
The one-handed controls are perfectly implemented, making it easy to play on the go. The 'Hero' system adds another layer, as different guardians provide unique abilities that can turn the tide of a desperate battle. It’s a bit more hardcore than your average casual game, but the sense of victory after clearing a difficult stage is immensely satisfying.
Available on: iPhone, iPad, iPod
Version 3.0.7Mon Feb 02 2026
[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%)
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!
Requires iOS 12.0 or later. Compatible with iPhone, iPad, and iPod touch.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!












Underdark: Defense is an atmospheric tower defense game where players must protect the last flicker of light against waves of dark forces. Featuring one-handed gameplay, it combines strategic tower placement with roguelike power-ups. Choose from unique heroes, upgrade your defenses, and adapt your strategy to survive the increasingly difficult nightly sieges.
Intuitive one-handed controls
Roguelike buff selection system
Powerful hero-based gameplay
Atmospheric dark fantasy art
Place your highest damage towers near the Eternal Flame for last-line defense. Focus on area-of-effect buffs early on to manage large swarms.
Earn trophies from victories to level up your guardians. Each level-up allows you to choose between randomized buffs that significantly alter your towers' power.
The game uses an energy system, but energy can be replenished over time or through rewards.