What is a dio?

Dio is the stage name of Ronnie James Dio, a heavy metal musician who was a vocalist and songwriter for several bands including Black Sabbath, Rainbow, and his own band Dio. He is widely regarded as one of the greatest metal vocalists of all time and is known for his powerful and distinctive voice. His songs often dealt with themes of fantasy, mythology, and the occult, and he was known for his vivid and theatrical live performances. Dio died in 2010 at the age of 67 from stomach cancer, but his legacy and influence on heavy metal music continue to this day.