Leonidas had a diamond ring which he believed once belonged to Charis.
History
Leo believed that the ring was Charis's. (AUDIO: The Temple of Questions) In fact, it contained part of Avril Fenman's essence and was part of her plan to get close to Bernice Summerfield through Leo and Ruth. (AUDIO: The Curse of Fenman) According to Traulus, the Epoch allowed Leo to keep the ring as they knew that it could play a role in convincing Bernice Summerfield to become a Hierophant. (AUDIO: Private Enemy No. 1)
Leo handed the ring to Benny to try to scratch the plastic-like floor that the Historians found underground (AUDIO: The Temple of Questions) and to cut into the Transuniversal Export call centre. When Traulus gave Benny the choice to become a Hierophant and restore the world as she wanted, he told her the truth of why the Epoch allowed Leo to have it. (AUDIO: Private Enemy No. 1)