There are ten Astrakeep buildings, spread over four floating islands. One rule drives everything else: the Crystal Tower's level caps every other building and unlocks new islands. Only one construction runs at a time, and it keeps going even when the game is closed. Here's what each building does and what to upgrade first.
This page is part of the Astrakeep guide. If you've only just started, read the beginner guide first.
The kingdom's resources
The kingdom runs on three building resources: wood, stone and mana. You earn them by fighting (every campaign siege you win gives wood and stone), raiding rival villages, sending heroes on expeditions, and from your production buildings. Resources also level up your heroes, so it pays to keep production going at all times.
The 4 islands and their buildings
| Island | Unlocked at | Buildings |
|---|---|---|
| Royal Isle | Tower lv. 1 | Crystal Tower, Sylvan Sawmill, Moonstone Quarry, Mana Well, Enchanted Storehouse |
| Warrior Isle | Tower lv. 3 | Rune Forge, Barracks |
| Arcane Isle | Tower lv. 5 | Arcane Academy, Summoning Altar |
| Merchant Isle | Tower lv. 7 | Cloud Market |
Every building goes up to level 15.
What each building does
Royal Isle: the heart and the economy
- Crystal Tower: "Heart of the kingdom. Its level caps every other building." It also sets your heroes' max level and the Tower level each campaign chapter asks for. At level 5, it lets you create an alliance.
- Sylvan Sawmill: produces wood.
- Moonstone Quarry: produces stone.
- Mana Well: produces mana.
- Enchanted Storehouse: "Raises the max amount of each resource." Every resource has a storage cap; the Storehouse lifts it so you can save up for big upgrades.
Warrior Isle: strength in battle
- Rune Forge: "Damage of all heroes: +n%". The most direct boost for winning fights.
- Barracks: "Hero HP: +n%". It also trains the four troops you play as cards in sieges, and its level raises your army space. Troops are covered on the troops and raids page.
Arcane Isle: magic and summoning
- Arcane Academy: "Special attack gauges: +n% faster". More frequent special attacks, which matter most against bosses. It also opens the "Research" screen: research that strengthens your economy (gathering, storehouses, construction, training and alliance help), one at a time, with no effect on battles.
- Summoning Altar: the portal where you summon heroes with tokens. It raises your "epic card chance". Everything about summoning is on the Astrakeep heroes page.
Merchant Isle: trade
- Cloud Market: "Merchants trade wood, stone and mana." Upgrading it improves the exchange rate. Handy when one resource overflows and another runs short. For each trade you choose the amount: a slider, the 25%, 50%, 75% and Max shortcuts, then a single button confirms the exchange.
What to upgrade first
- The Crystal Tower whenever you can. Everything hangs on it: building caps, islands, hero levels, access to chapters.
- Production and the Storehouse right behind, so each Tower level gets paid for faster.
- The Rune Forge and the Barracks as soon as you get stuck in the campaign: more hero damage and HP, and new troops (the griffin at Barracks level 3, the crystal colossus at level 5).
- The Arcane Academy for chapters with tough bosses.
- The Summoning Altar and the Cloud Market as needed.
Construction: one at a time, even offline
By default, only one building is under construction at a time ("A building is already under construction"). Construction keeps going even when the game is closed, and a "While you were away" summary greets you when you return, along with the resources produced. When less than a minute is left, you can finish it for free.
Tip: start long upgrades in the evening or before a break, and keep short ones for when you're actively playing.
The second builder
The second builder gives you "two construction projects at once (the Crystal Tower stays with the main builder)". Every new game gets it as a 3-day trial. After that, you can get it in the shop for good, or rent it for two days with gems. It's optional: it saves time, it doesn't add power.
Alliance help
In an alliance, you can ask for help on a construction: each help you receive takes time off ("+3 alliance helps: −…"), up to a set number of helps per build. Help others back, since that's what levels up the alliance. See the Astrakeep alliances page.
Speeding up without paying
Gems can finish a construction instantly, and an optional rewarded video can also speed one up, within a daily limit. You earn gems by playing: daily tasks and chest, first win on a level or against a boss.
Growing an archipelago between two sieges is what puts Astrakeep alongside kingdom building games on mobile. To watch your kingdom grow, play Astrakeep in your browser, or see the Astrakeep page.
Frequently asked questions
Why can't I upgrade a building?
Either it has reached the Crystal Tower's level, another construction is already running, or you're short on resources. Upgrade the Tower first, or wait for the current build to finish.
When do new islands unlock?
Warrior Isle comes with Crystal Tower level 3, Arcane Isle at level 5 and Merchant Isle at level 7.
Can the second builder upgrade the Crystal Tower?
No: the Crystal Tower stays with the main builder. The second builder works on the other buildings in parallel.
Do castle looks change anything?
No. Village looks on the world map are purely visual, with no effect in battle. To talk it over, join the Astrakeep forum.