This is everything you need to know about how to recruit Lynx in Chrono Cross: The Radical Dreamers Edition.
How to Recruit Lynx
The truth is, you can’t recruit Lynx — at least, not in the conventional sense as you have done with other party members!
Instead, you can play him for a short period of time. After completing Fort Dragonia (Another World), Lynx will change bodies with Serge. That means Serge will Lynx for a short period of time.
However, once you’ve used the Dragon Tear at Fort Dragonia (Home World), they will change back and you will never be in control of Lynx again. It’s impossible to get Lynx to actually join your party.