Royal Defense - Invisible Threat
The battles haven't stopped raging in the kingdom! Invisible Threat contains three new episodes for true tower defense fans. We've spent more time on balancing the levels for Steam players. We've also added new enemies to diversify the game. You'll need to use new tactics to beat them!
Offers
What are keyshops?Keyshops
Third-party resellers. Often cheaper, without official store support. Keyshop prices vs Steam →
Base game (1)
This is the base game required to play this DLC. Other expansions may also be required.
Multipacks (10)
DLCs (2)
About Royal Defense - Invisible Threat
Key Features
• Three new episodes
Wasteland – orcs have hidden amongst sharp and dangerous cliffs.
Fiery Plateau – destroy all the enemies on a burning plateau.
Mystic Valley – defend yourself against mystical creatures in an enchanted forest.
• Four new units, each with its own unique abilities.
Skeleton, Necromancer, Fire Elemental, Nature Elemental.
• Four new achievements. Unique quests made specially for the new episodes. Challenge yourself with exciting trials!
• The DLC also contains 150 free crystals for store upgrades. You can spend them however you like, since you don't need them to complete the game.
Please leave your comments and suggestions for improving the game and the genre!
Game details
Game details
Game modes
Languages
Royal Defense - Invisible Threat price history
Lowest tracked price: €1.39 (Jul 9, 2026) · current best: €1.62 across 2 stores.
Royal Defense - Invisible Threat reviews
67% positive reviews all-time.
Royal Defense - Invisible Threat — frequently asked questions
Where can I buy Royal Defense - Invisible Threat at the cheapest price?
Right now the cheapest offer for Royal Defense - Invisible Threat is €1.62 at GameBoost. KingsPrice compares 2 offers from 2 stores — official stores and keyshops — and refreshes prices throughout the day.
What is the lowest price Royal Defense - Invisible Threat has ever been?
The lowest price KingsPrice has tracked for Royal Defense - Invisible Threat is €1.39 (recorded on Jul 9, 2026). This covers the stores and period we monitor — set a price alert to catch the next drop to that level.
Is it safe to buy a Royal Defense - Invisible Threat Steam key from a keyshop?
Keyshops are marketplaces that resell game keys, usually below official store prices. The keyshops listed on KingsPrice deliver genuine Steam keys, but buyer protection differs from official stores — check the shop's rating and refund policy before buying. You can hide keyshop offers at any time with the keyshops toggle. Keyshop prices vs Steam →
How can I get Royal Defense - Invisible Threat at a discount?
Create a free price alert on this page and KingsPrice will email you when Royal Defense - Invisible Threat drops below your chosen price. The biggest discounts usually appear during seasonal Steam sales and publisher promotions — the sale calendar on this page shows the next confirmed event.
System requirements
Minimum
- OS *: Windows XP SP3
- Processor: 1500 MHz
- Memory: 512 MB RAM
- Graphics: OpenGL 3.0 compliant with 1.0GB of video RAM
- DirectX: Version 9.0
- Storage: 75 MB available space
Recommended
- OS *: Windows 7 or later
- Processor: 2000 MHz
- Memory: 1 GB RAM
- Graphics: OpenGL 3.0 compliant with 1.0GB of video RAM
- DirectX: Version 9.0
- Storage: 75 MB available space