Petra Martin is the purported grandmother of the twins Clio Martin and Thais Allard, though she is really a much more distant ancestor. She separated the twins at birth and had promised their mother, Clémence Martin, that she would keep the twins safe before she died. She is over 240 years old and her element is fire. She is a very, very powerful witch and healer. Petra had two daughters, Melita and Cerise Martin. During a ritual that was performed by her oldest daughter, Melita, her younger daughter Cerise died during childbirth. The ritual, however, made her and eleven other people somewhat immortal.
- Telepathy: She used this power to read Clio's Mind.
- Chlorokinesis: Petra used this power with a spell.