She starts out as an Egyptian slave girl from Gaul and after saving Xena's life becomes one of her teachers. She teaches Xena how to use pressure points, acrobatics and many other of what would later become her trademark moves. When Xena frees Caesar and returns him to his people she objects and senses the danger that lies ahead. Xena ignores her and is crucified by her would-be lover.
In the season 2 episode "Destiny". M'Lila is the one to free Xena from crucifixion and through the use of pressure points return feeling to Xena's legs. Later when they are located by Caesar's men she jumps in the way of an arrow meant for Xena. She dies in Xena's arms and it is this event which causes Xena to declare her purpose thereafter is death.
Notes Xena's armor design comes from the design on M'Lila's shirt.