Green Blood on a Black Rock is considered by many to be the most savage pit fight in Golarion. It takes place in the Sodden Lands, on a massive spire of ash rock that juts out of the sea. The tournament's notoriety has since spread beyond the Sodden Lands and is known in several parts of Avistan.
The Green Blood on a Black Rock tradition was started by the Free Captains of the Shackles, as the pirates pitted captured scrags (hence the "green blood") against each other on the now famous black rock. True trolls were introduced, and then a powerful half-dragon troll which was eventually defeated by a froghemoth. Today, there are no rules restricting the type of creature which can be entered, but all fights remain one-on-one.
The tournament itself is observed by the participating Free Captains and their crews who watch the fights from the decks of their vessels as they circle the Black Rock. In addition, some troubadours make a living by bribing their way aboard a participating ship. Afterwards, these "blood-bards" travel far and wide recounting authentic tales of the tournament's savagery. Finally, wealthy elites with access to scrying are known to watch the actual event live.