Schala Zeal is an important character from the Chrono universe. She is the princess of Zeal and is Queen Zeal's daughter and Janus's sister. She is kind and gentle by nature, and almost everyone in Zeal considers her a friend. In fact, she was one of the only people in all of Zeal to consider the Earthbound Ones as equals, and is the only one, besides perhaps Melchior, to respect Janus.
Schala was born in Zeal sometime before 12,000 BC. The Gurus said that Schala was much more powerful than her mother. The Gurus made her a pendant which she used to control magical items, specifically the Mammon Machine and various sealed doors. Queen Zeal knew this and ordered Schala to perform rituals she felt very uncomfortable with. She is also sensitive to the "Black Wind," something only she and Janus feel.
Schala first meets Crono and his friends when they visit Janus in his room. She sees that they have the power to save the Gurus (who have all either been in prison or run away), and after Queen Zeal captures Crono and his friends, Schala (and Janus) attempt to save them. However, the Queen's new prophet (who is actually an older Janus in disguise) makes Schala send them back where they came from.
Schala came to visit the Earthbound ones in Algetty after Crono managed to free Melchior from Mt. Woe. She swore to Melchior that she would no longer have any part in Queen Zeal's plans to use the Mammon Machine at the Ocean Palace and bring Lavos to her. However, Dalton kidnapped her and took her there anyway. Queen Zeal forced her to use her pendant to summon Lavos, and Crono and his friends arrived just as Lavos appeared. The power was too much for Schala to try and stop and her mother was embracing the power.
The prophet revealed that he was Magus (Janus's name from 600 AD) and tried to save Schala. However, Queen Zeal used Lavos to knock both him and Schala out. Crono then sacrificed himself, and Schala used the last of her pendant's power to send Magus and Crono's friends to safety.
In the original timeline (which had no interference from Crono or Magus), Schala presumably used her pendant's power to allow Queen Zeal and her to flee to safety. However, thanks to Crono's and Magus's interferences, Lavos and Queen Zeal forced Schala into the Darkness Beyond Time using a wormhole. There, Lavos absorbed her as a backup plan where she and Lavos became the Time Devourer. This caused Schala to have a split personality. Lavos controlled Schala and forced her to want to destroy the world. However, there was still good in Schala and she wanted to help herself, however, she couldn't do this completely. In order to save herself and her image, she cloned herself in 1,004 AD. She gave this clone her pendant and dropped her onto the world. Lucca found the clone and named her Kid.
In 1,006 AD, Schala heard Serge crying and tried to reach out to him. This caused a magnetic storm which started a chain of events leading to Frozen Flame, the source of Zeal's power now inside the FATE supercomputer in Chronopolis, choosing Serge as its Arbiter. In 1,020 AD, Serge was able to make use of a Time Egg to reach the Darkness Beyond Time. There, he fought the Time Devourer, and used Chrono Cross to free Schala from Lavos.