Metelbain Flowers were a species of flora that were once found in the Underworld but were believed to have become extinct. They were first mentioned in chapter 43.
The plant grows long, purple stalks with similarly-colored leaves with each stalk ending in a single flower. Each flower has a corolla of two petal sets, with a smaller one overlapping a larger outer one. At the center of each flower is a bulb which several white filament protrude from, each ending in a blood red anter. The bulb itself ultramarine, with the smaller set of petals being a lighter shade of blue than the bulb, gradually lightening in color towards the tips. The out set of petals are white, with the tips being a bright teal.
The flowers exude a refreshing lemon scent that is appealing to smell, however, inhaling the gas for more than three seconds will knock out any Azrael or Demon. The petals can also be ground and fermented, which doing so will release a noxious toxic gas.