Planescape: Brush with Oblivion
Slaad Lord of Entropy
The Slaad Lord of Entropy, Ygorl appears as a blackened skeletal hulk, wielding a large scythe. He rides a great wyrm brass dragon named Shkiv. As one of the exemplars of the Chaotic Neutral alignment, Ygorl is not truly evil, but still very dangerous, unpredictable, and self-serving.
Ygorl is the second oldest slaad lord, after Ssendam, and is considered the de-facto ruler of the Outer Plane of Limbo. He believes in bringing death, decay, and disorganization to the multiverse, and thinks this is best done by the slaadi, the truest agents of Chaos.
The Plane Below: Secrets of the Elemental Chaos suggests that Ygorl actually sprang into being the moment the multiverse finally died and has been perceiving time backwards ever since, so that the past is the future to him, and his “death” will be some time in the distant past. He is thus patient in his attempts to spread entropy, because he remembers the time when entropy claims everything, and regards it as inevitable.