Unnatural Selection

Unnatural Selection is the eighteenth chapter of Chrono Trigger.

Walkthrough
Crono, Ayla, and another party member (Marle, Lucca, Robo, or Frog) fly the Dactyls, to the Tyranno Lair.

Tip: You let the party heal themselves before you go on to the Tyranno Lair. You can use the happy water, or rest in the Chief Hut, in the Ioka Village. After they get to Tyranno Lair, get inside, and prepare to fight some Cave Apes, and Purple Reptites, which are stronger than the Green ones. If you see a cage with humans inside, it's the Laruba people, open the cage, and let them free. Head downstairs, and see some Reptites taunting somebody in the cage, which is Kino. After the Reptites are dead, watch a scene showing Ayla, freeing Kino. After Kino is free, he will show you something, follow him. When you follow him upstairs, he opens a skull (which is some kind of door with a dinosaur skull), and Kino comments Crono. Kino leaves the Lair with the Laruba people. On the way to find Azala, prepare to fight some Cave Apes, Reptites, Terasaurs, Avian Rexs, and Volcanites. Be sure to find lots of treasure!

Tip: If you get inside the room with the two Treasure Chests (that look like eggs), open the one on the left, that contains a Hi-Potion, don't use the one on the right, it's a trap door that will lead you to the prison cell where the Laruba people are, and you might be in combat with two Reptites, a Terasaur, and a Cave Ape.

Note: One of the rooms in the castle, have teleportation. They will lead you to different areas in the room. Look anywhere in the room for a teleporter that leads to treasure, although it'll be hard to find them, since they are invisible.

When you get to a room that Nizbel II is in, he'll tell the party where Azala is. Save your game, because you are about to fight him. Nizbel II is stronger than the normal Nizbel. His defenses will get higher when you attack, although it will lower with Light, but it one shock him, and freeze him, like the other Nizbel. Once Nizbel II is dead, keep going until you find Azala. She'll say will it be the Reptites that will rule the world, or humans? Because, the Red Star everyone in Ioka was talking about, and seen in the Dactyl Nest, is about to fall. After the conversation with Azala, you hear a loud ROAR! Azala runs outside, follow her. Azala is telling the Red Star to fall, then she finds the party in front of a big beast. The big beast is a Black Tyranno, and it is about to go on Attack Mode. Time to defeat the Black Tyranno, and Azala.

Tip: Be sure to fight Azala, before the Black Tyranno, it'll be good for one enemy out of the way. Be sure to use light on her.

After Azala uses 'Azala's Wrath', she flees from the battle. Then Black Tyranno will lower it's defenses, and boosts it's strength on flame. After five big roars, the Tyranno will start using Fire Breath on all the Party Members, twice! After that, the Tyranno will boosts it's defenses, and grabs a party member with it's tongue, and chews him / her, and spits him / her out. Then after a few seconds, the Tyranno will start lowering it's defenses, and boosts it's strength again. After the Tyranno is defeated, Azala falls down, and crawls towards the party. Azala, says that could the heavens have sided with the apes (humans). Then she says, that the Reptites have fought proudly to the bitter end. Then a big red light begins brightening, then Azala tells them that the giant star will fall in the earth, and start an Ice Age. Ayla calls the falling star 'Lavos', and it will show a scene showing a big spike ball with flames falling in the earth, which is Lavos! Ayla made up the name, saying 'La' means fire, 'Vos' means big. Kino arrives with the Dactyls, trying to save Ayla, Crono, and the other guy. Ayla wants Azala to come, but Azala refuses, because it is the will of the Earth. Ayla says to Azala, she will not forget her. Then Azala says to take care of this world. The Dactyls fly away, then Lavos hits the Tyranno Lair, with a BANG! Then near the ruins of the Tyranno Lair, the party realizes that Lavos was not created by Magus, it fell from space in Prehistory. Ayla asks Crono is he is gonna fight it. Then Ayla says to go to the place where Lavos fell. Then after they head inside the ruins, the third party member finds a Time Gate, and Ayla finds out that Lavos is deep under the Earth now. Time to go through the Time Gate, and see what is going on.

Note: You may head back to Ioka Village, and heal yourself, and find everyone in Ioka, and Laruba cheering, now that there are no more Reptites to interfere with humans anymore. Although there are still some Reptites taking Shelter in the Reptite Lair, and some in Mystic Mountains.