Clue: Legendary spinner's general aches isolated in the heart (8)
Answer: LACHESIS
Explanation: Definition: Legendary spinner
A hidden answer ('in the heart' – exactly) in 'genera**L ACHES IS**olated'. Lachesis was one of the fates; to be pedantic, sister Clotho did the spinning, Lachesis measured the thread of a person's life, and Atropos cut it off.