The Astrakeep campaign has 145 levels across 28 chapters: every chapter has 5 levels except "The Heart of the Star", chapter 19, which has 10. Every level is an enemy kingdom to besiege: you play troop, spell and hero cards across three lanes to bring down its two towers, then its keep. On the last level of each chapter, a boss guards the keep, and the story unfolds over six acts. Here's how the campaign is laid out and how to win the sieges that won't give way.
This page is part of the Astrakeep guide. Picking your heroes is covered on the Astrakeep heroes page.
How a siege works
Since the October 16, 2026 update, Astrakeep is no longer a tower defense game: there's no path to guard and no waves to hold back. In the game's words, "every level is an enemy kingdom to besiege: pick a card, send your troops and heroes down a lane, bring down its towers and then its keep."
- Energy and cards: an energy gauge refills on its own, and you hold a hand of 4 cards (troops, spells and heroes). Each card costs energy. "Last 30 s: energy ×2!"
- Three lanes: you drop a card in one of the three lanes, in your half of the field. Choosing the lane matters as much as choosing the card.
- Stars: the enemy has two towers and a keep. A fallen tower is worth 1 star, the keep 3.
- Special attacks: when a hero's special attack is charged, tap it.
The enemy defense is played by the computer, and there's no luck involved: every battle is replayed and checked by the server. The siege is shown in 3D, from a three-quarter view.
The troop cycle
"Each troop beats another (+50%)." Footmen ("Numerous: overwhelms guards") swarm shield guards, shield guards ("Sturdy: stops griffins") stop griffins, griffins ("Flying: brings down colossi") bring down crystal colossi, and colossi ("Giant: crushes infantry") crush footmen. Watch what the enemy sends down a lane and answer with the troop that beats it.
The 28 chapters and their bosses
| # | Chapter | Boss |
|---|---|---|
| 1 | The Floating Isles | Shadow Titan |
| 2 | The Frozen Peaks | Crystal Dragon |
| 3 | The Goblin Camp | Goblin King |
| 4 | The Shadow Realm | Void Lord |
| 5 | The Lava Forges | Mana Minotaur |
| 6 | The Forgotten Necropolis | Lich |
| 7 | The Crystal Caverns | Crystal Spider |
| 8 | The Cursed Marshes | Necromancer |
| 9 | The Storm Peaks | Shadowwing Queen |
| 10 | The Crystal Sanctuary | Crystal Golem |
| 11 | The Ash Dunes | Sand Scorpion |
| 12 | The Sky Fortress | Fallen Archangel |
| 13 | The Sunken Abyss | Abyssal Leviathan |
| 14 | The Elder Forest | Ancient Treant |
| 15 | The City of Gears | Clockwork Colossus |
| 16 | The Phoenix Nest | Blazing Phoenix |
| 17 | The Moon Gardens | Lunar Sphinx |
| 18 | The Void Citadel | Void Hydra |
| 19 | The Heart of the Star (10 levels) | Guardian of the Star |
| 20 | The Infinite Library | Living Grimoire |
| 21 | The Garden of Dreams | Dream Chimera |
| 22 | The Wing Yard | Brannok's Jailer |
| 23 | The Queen's Nest | Night Queen |
| 24 | The Ramparts of Dawn | Broken Archangel |
| 25 | The Empty Throne | Titan King |
| 26 | The Thousand Wings | Oath of the Seven |
| 27 | The Last Link | Shadow of the Seventh |
| 28 | The Open Heart | Last Nightmare |
Chapters 1 to 18 have 5 levels each (bosses come at levels 5, 10, 15 and so on up to 90). Chapter 19, "The Heart of the Star", is longer: 10 levels, from 91 to 100, with the Guardian of the Star at the end. Next come "The Infinite Library" (levels 101 to 105), guarded by the Living Grimoire, then "The Garden of Dreams" (levels 106 to 110) and its Dream Chimera. Chapters 22 to 28 go back to 5 levels each, from level 111 to level 145. When a boss falls, you see its defeat in full before the victory summary screen.
To open a chapter, you need to finish the previous one and have the Crystal Tower level it asks for: level 2 for chapter 2, level 10 for chapter 6, then level 15 from chapter 11 onward. After that the Tower no longer holds you back: only the strength of your heroes and troops moves you forward. If a chapter stays locked, the islands and buildings page explains how to level up the Tower.
Boss levels
On the last level of each chapter, the chapter's boss guards the enemy keep. Save your strongest cards and your heroes' special attacks for the moment your troops reach the keep, instead of spending everything on the first tower.
Six acts and the Chronicles of Astra
The campaign tells a story in six acts. You can read it back in the Chronicles of Astra, Orin's journal: every boss you beat adds a page, starting with the first one (level 5), and each hero's memories can be read on their hero sheet.
| Act | Chapters |
|---|---|
| Act I: The Shadows Wake | 1 to 4 |
| Act II: What Fell | 5 to 10 |
| Act III: The Price of the Sky | 11 to 18 |
| Act IV: The Heart | 19 to 21 |
| Act V: Those Below | 22 to 25 |
| Act VI: The Blank Page | 26 to 28 |
Acts V and VI
Acts V and VI carry the campaign on after "The Garden of Dreams": four chapters for Act V (levels 111 to 130) and three for Act VI (levels 131 to 145), guarded in turn by Brannok's Jailer, the Night Queen, the Broken Archangel, the Titan King, the Oath of the Seven, the Shadow of the Seventh and the Last Nightmare. We won't say more about who they are: that's for the campaign to tell.
An ending you choose
After the last boss, one final page opens in the Chronicles: "The Blank Page". The game offers you several endings, and you write the one you want. The choice is final. It gives no advantage in battle: it sets the last page of your journal and gives you a title to show next to your name.
The Ascension of Astra
Once the boss of chapter 1 is down (level 5), a second mode opens: The Ascension of Astra, "an endless spire to climb floor by floor: each floor holds a stronger kingdom to besiege." A guardian awaits every 10 floors. A floor you beat is yours for good, and the Ascension chest, which you open once a day, grows with your highest floor.
The Ascension runs in seasons. The kingdom leaderboard, for players and alliances, counts the floor you reach during the season, and the end of a season pays out gems based on your rank.
Winning a tough siege
A few principles that work from the first chapters:
- Pick your lane: put the pressure on one tower rather than spreading weak cards across all three lanes. A single fallen tower already earns a star.
- Follow the cycle: answer griffins with shield guards, colossi with griffins, footmen with colossi, guards with footmen.
- Pair heroes with their troop: each hero boosts a troop placed next to them. Kael and Varek lead the footmen, Lyra and Jinhou the griffins, Orin enchants the crystal colossi, Aurelion protects the shield guards, and Sylvara slowly heals every troop around her.
- Mix your army: with at least 3 troop types, each taking at least 15% of the space, your troops get +18% damage and health, and +25% with all 4.
- Play your spells at the right time: Arrows, Heal, Freeze and Shield are cards too.
- Keep something for the last 30 seconds, when energy refills twice as fast.
Automatic assault
You can let a siege play itself with Automatic assault. It's handy for replaying a level you've already won. On a tight boss level, take back control: choosing the lane and the moment for each card yourself gives you a better shot.
Rewards
Every level you win gives loot (wood and stone), and an optional video can double the loot ("Double the loot"). Your first win on a level and your first win against a boss also give gems.
What to do after a defeat
In order:
- Change your plan, it's free: another lane, a troop that follows the cycle, a hero next to the troop they boost.
- Check the recommended level ("Recommended heroes: lv. …") and level up your heroes.
- Upgrade the Rune Forge (damage of all heroes), the Barracks (hero HP and army space) and the Arcane Academy (faster special attack gauges).
- Add stars to your best heroes with shards.
- Replay levels you've already won to gather resources.
Astrakeep's campaign started out as a tower defense, and on October 16, 2026 it moved on to sieges, with the same taste for heroes and bosses. If you enjoy building a medieval kingdom and leading heroes, our page on kingdom building games on mobile covers that genre. To try the campaign, play Astrakeep in your browser: it's free. Astrakeep is also out on Android, on Google Play, with optional in-app purchases; the iPhone version is coming soon (see the Astrakeep page).
Frequently asked questions
How many levels are in the Astrakeep campaign?
145 levels in 28 chapters: every chapter has 5 levels except chapter 19, "The Heart of the Star", which has 10. The last level of each chapter is a boss, and all 28 bosses are different. The story unfolds over six acts; Acts V and VI cover chapters 22 to 28.
Is the Astrakeep campaign still tower defense?
No. Since the October 16, 2026 update, every campaign level is a siege: you play your cards across three lanes to bring down an enemy kingdom's two towers, then its keep. A tower is worth 1 star, the keep 3.
Why is a chapter still locked?
You need to finish the previous chapter and reach the Crystal Tower level that chapter requires.
Does the Astrakeep campaign have an ending?
Yes. After the chapter 28 boss, the Chronicles of Astra offer you several endings: you choose the one you want to write, once and for all. That choice doesn't change how strong your kingdom is. After that, The Ascension of Astra and its seasons take over.
Can a siege play itself?
Yes, with Automatic assault. That's enough for levels you've mastered; against a tough boss, picking your lanes and cards yourself works better. To share your strategies, head to the Astrakeep forum.