Star Palace & Northern Palace

Zodiac (Star) Palace

Upgrading the Zodiac Palace gives you star power, which you need to upgrade orange artifacts.

Zodiac Palace constellation map — The Zodiac Palace.

Which zodiacs to focus on

Stat	Zodiac	Target color
Mage attack	Capricorn	Purple
Archer attack	Sagittarius	Purple
Infantry attack	Pisces	Purple
Cavalry attack	Aries	Purple
Defense	Virgo, Gemini	Blue

You can still upgrade the others, but spend your materials on the zodiacs that give you the most stats first. Only move on when you have extra. Keep raising your attack zodiacs toward Purple and your defense zodiacs toward Blue.

Virgo stats overview — Virgo: includes damage boost when defending.

Gemini stats overview — Gemini: includes damage taken reduced when defending.

Capricorn stats overview — Capricorn: mage attack and damage.

Sagittarius stats overview — Sagittarius: archer attack and damage.

Ruins Shop with Birthstone Chest and Polycrystalline — The Ruins (Star Mine) shop.

Northern Palace

The Northern Palace was nerfed. If you have the currency to upgrade it, sure, but the stat gain is small compared with other items. Ignore it for now.

It was buffed a little when the 3rd and 4th constellations were added, but it's expensive. Whether it's worth it depends on how much you can spend.

Northern Palace with Ursa Major and Perseus — Northern Palace: the original two constellations.

Northern Palace with Pegasus, Lyra, Ursa Major and Perseus — Pegasus and Lyra were added later.