Dark Mantles, an innate ability available only to members of the Sin-Born clans. By concentrating their infernal energies in their banes or sins and releasing them as one force-field, members of the Sin-Born clans could summon their Dark Mantles, mauve robes that not only multiplied the might of their offensive, defensive and spiritual abilities, but also enabled them to unleash crippling domain abilities based on said banes and sins.
The powers and boons provided by a Dark Mantle directly depended on the Sin-Born clansmen's rank in the Myriad Abysses' hierarchy, because yes, Sins and Banes were all born with ranks—ranging from the lower D rank to the upper S rank.
Each rank had a lower and upper rank, with all Sin-Born clansmen being able to improve their rank as long as they kept devouring corrupt lives or foul energy sources.
