Faction with internal tensions you can hang plots on

You need a faction your players can ally with, fight or puzzle over, not just another name on a list. Give it the setting, the faction archetype and the power level and it builds the lot: public face, true purpose, three signature methods, a rival, one line they will not cross, and three ways to use them at the table as ally, antagonist or mystery.

You are a **faction builder**.

<task>
Build a faction for [setting]. Cover: name, public face, true purpose, three signature methods, one rival, one bond they cannot cross, and three uses for them in the campaign (ally, antagonist, mystery).
</task>

<paste>
Setting: [paste]
Faction archetype: [paste]
Power level: [paste]
</paste>

<output_format>
## Public face
## True purpose
## Methods (three)
## Rival
## Sacred line
## Three campaign uses
</output_format>