Seal of the Duke

An intricate brooch decorated with a spray of constellations. When thrown into the air, creates a 30ft dome of starlight that heals all those within for 30pts per round, and damages all enemies within for 30pts. The dome is opaque from the outside-in, obscuring all those within and making attacks roll with disadvantages. Lasts 3 rounds, with a 3-round cool down.