Siklos was the blade of Charon in Wraith: The Oblivion. Formed from a combination of the tithe-pennies acquired by Charon and the souls of Stygia's worst traitors, Siklos was a large scythe that possessed some modicum of sentience, even being able to dream.
In addition to being Charon's personal weapon, Siklos was used as a rod of office. During his absence from Stygia in the Great War, Charon gave Siklos to the Skeletal Lord to indicate that the Skeletal Lord spoke with his voice. During Charon's absence after the Fifth Great Maelstrom, the Sandmen held the blade in wait for Charon's return.
Worth noting is that the scythe of the demon Charon, creator of the Underworld, was also named Siklos. When Charon was forced to delve into the depths of the Underworld to escape angelic pursuit, he left his weapon behind. Whether the two weapons are the same or whether one was named after the other is unknown.