Thanatos is the oldest and most powerful Immortal of the Sphere of Entropy in the D&D setting of Mystara. He hates all life and seeks its total destruction, but only on his terms and no one else's. He is constantly juggling various schemes and plans which he hopes will bring this goal to fruition.
In the Blackmoor setting, Thanatos was once a wizard that specialized in the delivery of magical diseases. Using this knowledge, he created his own magical disease that managed to spread to Temrin, the god of time. The disease killed the god, but didn't spread further Sollus eradicated it, and Thanatos collected the dead gods power, using it to ascend to godhood, taking his portfolio over time, as well as disease and famine. Thanatos has since then been working on a way to spread death and famine to eradicate the "disease" that mankind is to him.
