Bind Sidereal Servitor (True Ritual)

This ritual must be cast between sunset and sunrise, under a moonless sky with stars visible.  It requires drawing a circle 15 feet across, inside which the caster and other participants stand.  The ritual then lasts until the servitor's task is fulfilled, or it is dismissed by the caster.

At the end of the ritual, a sidereal servitor appears outside the circle.  You issue a command to the servitor, which it must be capable of performing withing 100 feet of a point within range.  Typical commands are "Protect the treasure in the cellar beneath my keep." and "Attack anyone who trespasses in my house."  The servitor cal also be commanded to only attack a single named enemy who comes within its territory, or even to build a structure (provided all necessary materials are available to the servitor within its territory).

If you issue a command to the servitor that it cannot fulfill within these parameters, it attacks you and fights until either it drops to 0 hit points or you are dead.

You can dismiss a sidereal servitor by speaking a ritual phrase of unbinding to it in a language it understands.  You must be within 100 feet of the servitor to do this, and it must be able to hear you.