Ayla's name could be an allusion to Jean Auel's Earth's Children series, the protagonist of which is a tall, light blond-haired, blue-eyed, prehistoric girl named Ayla. It could also refer to the tayra (Eira barbara), as her outfit contains a furry tail akin to one of these animals.
Ayla was brash, confident, and had a strong-willed personality.
Prior to the year 65,000,000 B.C., Ayla became chief of Ioka village due to her strength and fearlessness, acquiring a Piece of the Dreamstone as a symbol of that office. She led her people in the war against the Reptites, assumedly since the beginning of her time as chief. When the mysterious time-travelers from the Future arrived, Ayla temporarily relinquished her post to join them in their quest to stop Lavos. Kino, her mate, probably served as chief in her place. Outside the Forest Maze, right before the defeat of Nizbel in the Reptite Lair, she mentions that upon falling terminally ill or upon dying, Kino will become chief of the Ioka Village. Because of this, it seems that the title of chief does not necessarily travel to the strongest or most courageous of the Iokan Tribe, but rather, progresses to the spouse or the next genetic heir, much like the monarchy that exists in following eras.
After Lavos hits the planet, dust blasts into the atmosphere and blocks out the sun. This causes an ice age and the extinction of the Reptites; Ayla subsequently retires from her duties as chief; and after the defeat of Lavos, Ayla returned to the time era 65,000,000 B.C. and then she married Kino with a Dreamstone ring. As she is the distant ancestor of Marle and the Guardia Royal Family, she and he produced a lineage that survived the Ice Age and even survived the Fall of Zeal.
It is unknown whether Ayla reassumes her role as chief after her pregnancy. Upon her death, likely one of her children took her place as chief. A Female child would be more likely to fill this position.
Ayla is first introduced to the party when Crono and his friends visit the prehistoric era to repair Frog's sword, The Masamune, to assist in their battle against Magus, leader of the Mystics and murderer of Frog's best friend Cyrus. The broken pieces of the Masamune are acquired after the party defeats Masa and Mune, the guardians of the blade. The shards are taken to Melchior, a swordsmith and Guru, who cannot repair the blade without Dreamstone, a crimson-colored rock of ancient origin--so ancient that the party must travel millions of years into the past to recover a sample. Upon their arrival in Mystic Mountain, they are ambushed by a seemingly ceaseless swarm of Reptites. Ayla shows up to fight them off and invites the time-travelers to her village for a party. Ayla, as chieftain due to her strength and will, is the keeper of the Dreamstone, and during the party, if Crono beats Ayla at an alcohol-chugging competition (censored in the English version as "soup"), she willingly forks it over. However, when the sun rises the next day, they find the camp has been ransacked by Reptites and the Gate Key stolen. Tracking the reptilian marauders to Forest Maze, Ayla convinces Kino to admit he had stolen the Gate Key out of jealousy, after which point the Reptites stole it from him. Ayla, Crono, and the others invade the Reptite Lair, defeat Nizbel, and take the Gate Key from Azala so they can return to the present and repair the sword.
She does not appear again until the battle against Magus transports the party back to Prehistory. Alongside Ayla, Crono and the others battle the Reptites and witness the origin of Lavos at Tyranno Lair. As the alien parasite falls from the sky as a "Red Star", Azala predicts an Ice Age will claim the land. It is at this point that Ayla names "Lavos", a word she made up from the root words "La" meaning "fire" and "Vos" "big" in the Iokan language.
Ayla's strong morals convince her to join the party permanently after this.
In Chrono Cross, Ayla does not make an appearance in the game; but however, a young girl from a prehistoric era named Leah bears a strong striking resemblance to her in manner and appearance. She also says to Serge at the end of the game that she will name her child "Ayla", the name meaning "New song of land" according to her.
Ayla cannot use magic because she was born before humans became genetically capable of doing so (as further explained through human evolution in Chrono Cross). Highly dexterous, Ayla travels and attacks with her hands and feet, reminiscent of felines.
She relies on unarmed combat and physical prowess in battle. Unable to equip weapons to assist her in battle, she instead receives upgrades to the critical hit rate of her Fists. At Level 72, her critical hit raises to 35% and inflicts the Status Effect, Confuse. At Level 96, her critical hit damage increase to 9,999 damage, much like Robo's Apocalypse Arm, the primary difference being that this weapon inflicts normal damage on non-critical hits. Exclusive to the DS release of the game are two more upgrades that bridge the gap between Level 1 and Level 72. The upgrade at Level 24 increases her critical hit rate to 25%, whereas the upgrade at Level 48 boosts it to 30%. After this, her fists upgrade to as they normally would in Super Nintendo Entertainment System release.
Departing from the usual role of female characters in role-playing games, Ayla is a physical damage dealer. Physically, she is the strongest character in Chrono Trigger, and is able to take the most damage next to Robo. Unlike the other characters, Ayla doesn't equip a weapon and instead fights with her bare hands, and her fists upgrade as weapons as she levels up. This makes her cheaper to equip than other characters since she only needs to equip armor. Interestingly, in full-motion video present in the PlayStation release of the game, Ayla attacks enemies with a club. This never appears in the game. All of her techs focus on dealing with physical damage, except her Charm tech, which is used to steal items, and Kiss which heals only one character.
Because she is the only one who can take items from enemies with Charm, she is essential on rare opportunity battles like bosses that contain a rare item that may not be available later on.
Although Ayla cannot use any magic, she has a small percentage of resistance against Fire magic (each character has a small resistance against something). This suggests that if Ayla had the genetics for magic, she'd be a Fire innate-like Lucca. Further driving home the point, Ayla's name is composed of two syllables, "Ay" and "La" respectively. She admits that "La" in Iokan tongue means "Fire", and "Ay" in conventional English is an affirmation or a tongue-in-cheek version of the pronoun "I" (in other words, "I fire"). However, compared to the other characters, her magical resistance overall is lower than normal.
The only way Ayla can do elemental damage, she needs to combine with another character with techs. Thankfully, her high damage output combined with an elemental magic attack can greatly amplify the damage.