Matrona Kani was Crozier’s assistant during his surgery on Kiv in 2379. She also served as Kiv’s head servant, being responsible for instructing the others. (Mindwarp)
On Thoros-Beta, Kani served the Mentors and was in charge of all of Lord Kiv’s female servants, herself keeping a number of personal maids whom she demanded called her “Matrona”. She was charged with providing Kiv with his medicine and was assigned to assist Crozier with his experiments into saving her master’s life.
During an experiment on Yrcanos, the two were interrupted, provoking her anger. She was initially disbelieving of the Raak’s regression and recognised how damaging that was to Crozier. She helped Crozier and the Sixth Doctor with Kiv’s physical transfer and later admitted Peri Brown into her personal household, oblivious of her connection to The Doctor until she was discovered.
The Matrix showed the Matrona shaving Peri and helping transfer Kiv’s consciousness into her before Yrcanos killed both Peri (Mindwarp) and Crozier. (Mindwarp) However, this was found to be a lie,
(The Ultimate Foe) with the transfer actually having been a failure. (Antidote to Oblivion)
The Matrona was an interested pupil, curious about Crozier’s work and asking questions whilst assisting him. She could be angry, quickly snapping upon being interrupted, her voice having the effect of whiplash, but sometimes her soothing voice was all that could calm Lord Kiv. Her influence provoked Sil’s jealousy. (Mindwarp) She preferred to have some individuality in her household, leading her to keep some unprocessed maids. (Mindwarp)