Dian Cecht is the god of healing and medicine of the Irish Tuatha De Danann, their divine physician. In the tale of the Second Battle of Mag Tuired he presides, with his children, over a well of healing into which the mortally wounded are dipped and from which they emerge whole, restoring the warriors of the Tuatha De Danann to the fight.
When King Nuadu loses a hand in battle, a blemish that, under Irish custom, disqualifies him from kingship, Dian Cecht fashions him a working silver hand, earning the king the name Nuadu Airgetlam, of the Silver Arm. But the story turns dark: when his own son Miach surpasses him by causing flesh and blood to grow over the stump, so that Nuadu regains a true hand, Dian Cecht, consumed by jealousy of the greater healer, strikes his son dead, and from Miach's grave, it is said, sprang the herbs for every ailment of the body, which Dian Cecht then scattered and confused, so that their full knowledge was lost to humankind.