The Master (Doctor Who)

Context: Unlike the Doctor, the Master does not usually have companions. There have been times when he made exceptions, though in his case they are not so much "companions" as "tools". In Castrovalva, the Doctor's companion Adric was abducted by the Master and forced to create a block transfer computation. Later, in The King's Demons, Kamelion is controlled by the Master before the Doctor steals him away, with the Master regaining control of Kamelion in Planet of Fire. In the second episode of The Ultimate Foe, Sabalom Glitz chose to go with the Master in search of Time Lord secrets.  In the 1996 television movie, Chang Lee helps the Master because he has been duped into believing that the Doctor had stolen his body. When Lee begins to realise the truth behind the Master, his loyalty begins to falter, therefore the Master attempts to kill him without hesitation. In promotional media surrounding the movie, Lee is depicted more as a companion to the Eighth Doctor (alongside Grace Holloway), and was referred to as such in a documentary series released as part of the 50 year anniversary celebrations, The Doctors Revisited - The Eighth Doctor.  In "Utopia", Chantho plays a similar companion role to the Professor Yana persona. Chantho states that she has been with him for 17 years as a "devoted assistant". Later, when the Master persona resurfaces, he berates her for never freeing him from his confinement and the two fatally wound one another, resulting in Chantho's death and the Master's regeneration.  In "The Sound of Drums", the Master, as Harold Saxon, is married to Lucy Saxon, to whom he refers at one point as his "faithful companion". Lucy is aware of the nature of the Master's plans yet is still loyal to him. She has travelled with him to Utopia, the end of the universe, and thus believes "there's no point to anything." Their relationship appears to be non-platonic; they kiss quite often and it seems as though their marriage is more than just a pretence. Lucy comments, "I made my choice, for better or for worse." In "Last of the Time Lords" she is still present, but showing signs of apparent physical abuse, and her loyalty towards him begins to waver. She shoots the Master at the climax of the story, killing him. She is imprisoned, but when the Master's coven made the preparations for his resurrection in The End of Time, she is forced into giving the Master's biometric signature on her lips to complete the ritual. Having foreseen his return, Lucy threw a vial containing a chemical to disrupt the resurrection, killing herself in the resulting explosion while only succeeding in giving the Master a tentative life.  Although not a companion in the traditional sense, the Master allied himself with another evil renegade Time Lord, the Rani, in The Mark of the Rani to thwart the Doctor. The Master has also been known to ally himself with other villains of the series, including the Daleks, the Cybermen and the Autons. None of these alliances lasted past the Master achieving his own aims, or his being stopped by the Doctor. CANNOTANSWER

Question: Did Doctor Who have any other companions other than Lucy Saxon?
Answer: Chantho plays a similar companion role to the Professor Yana persona. Chantho states that she has been with him for 17 years as a "devoted assistant