This Yklwa has been blessed by the Guardian itself ands its sharp edge has been replaced by many different shards of a holy steel mirror that has defied an oni 

A yklwa (pronounced YICK-ul-wah) is a simple melee weapon that is the traditional weapon of Chultan warriors. A yklwa consists of a 3-foot wooden shaft with a steel or stone blade up to 18 inches long. It costs 1 gp, and it deals 1d8 piercing damage on a hit. Although it has the thrown weapon property, the yklwa is not well balanced for throwing (range 10/30 ft.).

Notes: Damage: Radiant, Advantage: Ability Checks, Thrown