The game features an unusual setting of a huge rock sphere that floats in a vast ocean of lava. The religious culture of the sphere equates human blood to the lava pool. Characters in the game are all Blood Singers, able to sing magical songs that cause magical effects by causing self-wounds that bleed, releasing the blood power and allowing it to link to the lava power.
Characters have Stats (Attributes), including Blood, Song, Sphere, Spirit, and Light Affinity. Stats have a numeric value ranging from 1-6 (some are capped at 3), distributed from a point pool at character creation. Characters also have Talents (Skills) selected from a brief list. Action resolution uses opposed dice pool rolls, with each roll yielding a success count - the opponent with the most successes wins.