Alice

Ace was an individual who travelled with the Professor. (PROSE: Republica)

Behind the scenes

 * Ace is strongly implied to be the same Ace that travelled with the Doctor and in the original audio drama she was played by Sophie Aldred. Various people involved, including Aldred, felt this was too blatant a copy of Doctor Who and the BBC would send a legal warning over it. The second series of audios would rename her Alice; Nigel Fairs suggested this name due to its similarity to Ace. (REF: Downtime – The Lost Years of Doctor Who)
 * In the Republica novelisation, a cleric refers to Ace as a "myriad" and mentions four personas, including "Dorothy [the original Ace's real name] in the cyclone, Alice down the rabbit hole".