Mordechai Muniz, also known as the Old Master, is a former Mossad agent.
Mordechai Muniz joined the Mossad at a young age, and eventually rose to become its head. In 1960, he was part of the team that abducted Adolf Eichmann from Argentina, and the Black September mastermind.
Even following his official retirement, Muniz continued to hold much influence in the Mossad, and continued to work for them in an unofficial capacity, being nicknamed the Old Master. Muniz would be allowed to work out of the Dimona Nuclear Research Centre, where he kept his Living Trophies.
When Stretch was captured by Jack "Wolf" West Sr. and his forces, he decided that they would hand Stretch over to Muniz for the reward.
Wolf handed Stretch over to Muniz, who immediately began imprisoning him in one of the Living Tomb tanks, telling him that this was a better punishment for enemies of Israel than death.