Queen Zeal (ジール "Jīru"?) is the matriarch of 12,000 B.C while she serves as the secondary antagonist of Chrono Trigger. She is the sole ruler of the Kingdom of Zeal, the most magically advanced civilization throughout Chrono Trigger 's timeline. It is unknown how the Queen came to obsess over the power of Lavos, but by the time Crono and his friends encounter her, she is dangerously fixated on drawing upon Lavos's energies in an effort to become immortal.
Zeal is maniacal in her efforts to gain power and immortality. She is haughty, cruel, and singleminded. Her own people are both slavishly devoted to her and terrified of her. She is paranoid and manipulative, gladly abusing the vast magical talent that her daughter Schala displays in order to further her goals. She shows no concern for the number of Earthbound lives lost in her attempts to reach Lavos' power and does not even seem to care for her children.
However, it is mentioned by many, including the Gurus, that Queen Zeal did not always behave in such a power-hungry and inhuman manner. Melchior observes that the Queen's psychological degeneration appears tied directly to how much of Lavos' energy she absorbs through the Mammon Machine. Though Schala recognizes her mother's madness, she remains emotionally torn over her inability to accept her mother's behavior. Janus (Magus), the Queen's only known son, reveals his feelings that Queen Zeal has ceased to be his mother, that she has somehow been changed by the power of Lavos.
It is during the rule of Queen Zeal that humanity first comes into possession of magic, which is revealed to be a concentrated form of Lavos's power. It is this power which Zeal believes will make her immortal. Indeed, after the events in the Ocean Palace and the rising of the Black Omen, Queen Zeal does seem to obtain some form of immortality since she exists in any time period that the Omen can be found in. Queen Zeal makes her final stand against Crono at the heart of the Black Omen, where she is finally defeated. It is mentioned by Gaspar afterward that she reverts to a normal human being.
It is important to note that Queen Zeal is unique in terms of her relationship with Lavos. She is the only known entity to establish any sort of a rapport with the creature. She treats Lavos as a god-like being worthy of worship, yet at the same time Lavos makes no attempt to absorb or destroy her, and indeed seems to follow her commands during the fateful encounter in the Ocean Palace. Also potentially noteworthy, Lavos does not mimic her powers during Crono's encounter with him, despite the fact that she is one of the most powerful boss characters in the game. All of this may suggest a unique relationship between the two, with Zeal's worship both drawing strength from and channeling power into Lavos. However, the actual dynamic of their relationship is never fully explored, and one can only speculate as to its true nature.
The word Zeal means to pursue something passionately, as this Queen pursued immortality through Lavos, at the expense of her children, her associates, and her home.