Lavos second form was the most annying because of its opening attack (ussualy killed Chrono ) but i won at lv 40 I used Chrono with Rainbow,haste hat,nova armor, and prism specs and just had him cast luminair over and over I had Magus with same equip cepst magic seal and star scyth and used Dark bomb on the arms (i didnt have him learn dark matter yet ) and From with masamuneII Prisim helmet, Nova armor, and gold earring to max hp and had him cast cure 2 (probably should have had him have a haste hat instead of magus) . The first round of second form Lavos will probably kill chrono but frog and magus should survive have one revive then have other use a mega elixer to heal everyone then just keep casting Luminair and Dark bomb (dark matter if you have it) and have frog heal when needed which wasnt to often follow these instructions and you can beat lavos without a problem at lv 40