Raise a Church (build menu, big stone footprint). Stand next to it, press E to open the clan UI. From there you can found a new clan or join an existing one if you've been invited.

Clan name must be 3-24 characters. The cap on members is 10.

Every storage building (Silo, Shed, Woodcutter, Quarry, Blacksmith) has a "share with clan" toggle in its header. Once on, every clanmate can deposit and withdraw, and can assign their slaves to work there.

Doesn't affect Houses or the Church. Your stable's still yours.

At the Church, an officer can declare war on another clan. Once declared:

• You can fight opposing clan members anywhere on the map — the deadzone gate is lifted.
• Their slaves are fair game.
• Truce is called from the same Church UI.

Anyone can leave their clan from the Church. The leader can disband the whole thing the same way — every shared building reverts to its original owner.