Castle Heart

The Castle Heart is the first thing required to be built before you can start expanding your territory with tiles, which must be connected to it. Once the tiles are in place, additional structures may be built on top of them.

Castle Hearts require upkeep in the form of. It will remain powered for 24 hours per. Running out of blood essence causes your territory and its structures to decay, and prevents crafting stations from functioning.

The castle heart is not required to be placed inside the castle you eventually build. Its only requirement is to be connected to the territory, although it will be vulnerable to attack if placed outside a walled area.

When moving the Castle Heart, all tiles must somehow connect to the new Castle Heart location.

Upgrading the Castle Heart to Level 2 will unlock Stone Wall & Flooring in the foundations building menu.

Upgrading the Castle Heart to Level 4 will unlock the Vampire Power.

Upgrades
Your Castle Heart can be upgraded to increase its max Border tile capacity, its Servant count and its castle power slots.

Destroying & Claiming
Rivaling castles may either have their defenses disabled, destroyed or claimed with 1 or 3 Castle Keys respectively by interacting with their Castle Heart. However, the castle must have first been breached by a Siege Golem or be in decay from running out of before hostile actions can be taken. When a castle is claimed, every structure will be transferred to the claimant, including Prisoners & Servants. The type of key required must correspond to the level of the Heart attempting to be accessed. For example, a can only access level 4 Castle Hearts, not level 3s.

On PvE servers, even though there's no threat of raiding, castles may still be destroyed if in decay.

It should be noted that everything mentioned above is server-specific.