The Old King's Crown · Board game rules
Can you purchase any Site of Power card?
Quick answer
You may only purchase Advanced Faction Cards and HQ Cards from your own Faction's Site of Power, not from opponents' Sites of Power.
Details
Your Site of Power contains your Faction's Advanced Faction Cards and HQ Cards, which you can acquire by spending Lore (☐) from your Supply. [p.44 — Sites of Power] You may acquire any number of these cards at the same time as long as you can pay their associated Lore Costs in full. [p.45 — Acquiring Cards From Your Site of Power]
When you acquire an Advanced Faction Card, it moves to your Hand (or to the top of your Deck if your Hand is full). [p.45 — Acquiring Cards From Your Site of Power] When you acquire an HQ Card, it moves to your Supply instead. [p.45 — Acquiring Cards From Your Site of Power]
You can only spend Lore when you add Lore to your Supply—typically through Journeying or other abilities. If you don't spend it immediately, that Lore remains in your Supply and you can spend it the next time you gain more Lore. [p.45 — Acquiring Cards From Your Site of Power]