He was the daemon of peaceful death.
His touch was gentle, likened to that of his twin brother Hypnus. Violent death was the domain of Thanatus’ blood-craving sisters, the Keres, daemons of slaughter and disease.
Thanatus could occasionally be outwitted, a feat that the sly King Sisyphus of Corinth twice accomplished. When it came time for Sisyphus to die, Zeus ordered Thanatus to chain Sisyphus up in Tartarus. Sisyphus cheated death by tricking Thanatus into his own shackles, thereby prohibiting the demise of any mortal while Thanatus was so enchained.
Eventually Ares, the bloodthirsty god of war, grew frustrated with the battles he incited since neither side suffered any casualties. He released Thanatus and handed his captor over to the god. Sisyphus would evade Death a second time by convincing Persephone to allow him to return to his wife stating that she never gave him a proper funeral. This time, Sisyphus was forcefully dragged back to the Underworld by Hermes when Sisyphus refused to accept his death. Sisyphus was sentenced to an eternity of frustration in Tartarus where he rolled a boulder up a hill and it would roll back down when he got close to the top.