This is everything you need to know about how to recruit Macha in Chrono Cross: The Radical Dreamers Edition.
How to Recruit Macha
You’ll meet Macha after your time in Viper Manor, when Kid is poisoned.
When it comes to how to recruit her, you’ll have to make a heartless choice. After Lynx poisons kid, you’ll be faced with a decision: save Kid or not? You’ll have to choose not to (though don’t worry, Kid survives anyway).
Keep going with the story and when you wrap up in Termina, you should head back down to the docks and tell Macha you want to leave. After Glenn approaches you, she will tell you she is worried about you and ask to join you.
Simply let her to have her join your party.