Brain and Brawn Ship series

Born a hopeless cripple, Helga's parents gave her excellent brain to Central Control for the specialized training and adaptation that turned her into one of a special class of sentient spaceship. Her passion for music and her superb, though artificial voice, was a source of solace, pleasure and even protection in her journey among the stars. As number 834, Helga was known as the ship who sang.

A shellperson named Tia searches for the EsKays, a star-faring race whose fate is a mystery and to seek out whatever it was on the EsKay planet that caused her neural disorder. Then she plans to eliminate it so that no other child will ever suffer her fate.

"Alas, intelligent life is thin on the galactic ground, so when Carialle and Keff arrive on a very nice little world with very nice little aliens, fuzzy and polite and eager to please, they are overjoyed...(until the evil powerful sorcerers controlling the "fuzzies" show themselves).