Chrono Trigger/Magus's Castle

Chapter 15: Magus's Castle (600 A.D. third time)

Magus's Castle
Incidentally, Ozzie Slash and Flea are actually rock musician references, Ozzie Osbourne, Slash from Guns n' Roses, and Flea from the Red Hot Chili Peppers, which is why one of the townspeople refers to them as tone-deaf evil fiends.

Anyway, make sure you had Spekkio teach Frog water magic before you begin, and determine who you want your third party member to be. Magus uses barriers of all the different magic types, and Crono and Frog have lightning and water respectively. Marle would be redundant with ice magic, so I'd go with Lucca or Robo for fire or shadow. The beginning of Magus's castle is very eerie, simply follow both paths to their conclusion and come back to the save point in the center to greet Ozzie and begin taking on Magus's henchmen. Head down the left path for Slash, the right path for Flea. I'm going to go with Slash to start since you get a sword for fighting him.

Slash
Anyway, going down the left path to fight Slash, talk to the Omnicrones in the next two rooms if you want to fight the skeletons. In the last room with the sword on the wall, talk to the lady at the front of the room to fight the skeletons there, and then Slash will confront you. You'll have to fight him in two stages, before and after he picks up his sword. Healing will probably be very important for this battle, if Frog knows heal you're set or if you have Robo with heal beam you can heal the whole party in a single turn, otherwise try the Aura whirl or have one party member use mid tonics or simple healing spells. Afterwards have Crono pick up and equip the Slasher.

Flea
Backtrack and go down the right path to face Flea. Talk to the bottom kid if you want the treasure chest, these monsters are pretty easy anyway. Keep going through the room and talk to all of the phantoms impersonating someone close to each of your party members if you want to get into some more monster fights. You'll then run into a monster who's impersonating the magician Flea. Make sure whatever character kills it or has low MP, since whoever finishes it off will have all their MP drained. On a side note, if you counter-attack a monster with a counter, its counter doesn't work so if you have the rage band equipped and it strikes you, you can kill it without getting your MP drained.

After you beat the weird monster, the bat that was following you around will turn into the real Flea. If you're at low (i.e. normal) levels healing will be your biggest priority, although you can get by without a tech that heals all your party at once, you'll probably just have to spend a few rounds getting yourself back to full health before continuing, and make sure you save first. After you beat Flea s/he'll leave behind a magic tab.

Ozzie
Head back to the front of the castle and step on the save point to warp forward. You can skirt the edges of the room to avoid most of the monsters or run the gauntlet down the center to fight them. Pick up the mist robe at the end and give it to one of your favorite girls, then talk to Ozzie to chase him away. The next room will be full of conveyor belts and falling anchors, so run as you cross them and be careful. You can also walk against the conveyor belt to stay in place if you need more time to cross. Pick up the chests and chase Ozzie into the next room.

The only way to trigger a fight in the next room is by running into the green ball, and previously mentioned you don't get into a fight with monsters unless you're moving yourself. So stay still to let it pass you rather than worrying about climbing the ladders. In case you fight a juggler, it alternates between physical and magical defense. If you hit it with a weapon it'll turn on its physical defense, and if you hit it with a spell it will turn on its magical defense. It can only have one on at a time, and it starts with physical defense on.

In the next room Ozzie will have a bunch of fake platforms that fall out of the floor, leading you to a pit filled with skeletons the first time. I'd recommend falling down at least once to pick up the items and get the magic tab in the bottom right corner. There are four save point things, one of which is real, one of which is a transport out, and two of which are monsters. The fake save points are an excellent source of experience and present no challenge, so I'd fight as many of them as possible. You might want to use a shelter at the save point too since you're probably drained from Slash and Flea.

Once you're through the room you'll pass into another walkway section where either the outlaws or the roly balls can get you into a fight. The next area will have sets of enemies arriving on chains, hopefully Frog has the heal spell by now so you can recover between fights. The Jugglers switch between being immune to magic or physical attacks like I said, so try to start off with a multi-target spell and finish them off. The outlaws will do a group counter-attack if you attack them while a juggler is still alive. The next room is another long hallway, you can walk around the statues or charge down the center to fight. Hopefully you have whoever is casting spells to kill the jugglers equipped with the silver stud.

In the next room you'll finally get to fight Ozzie. Don't worry, he's a joke. Pick up the two chests, then engage him and only aim at the switches while you're fighting. Hit each of the four in turn as you're able to target them and Ozzie will clink to his doom. Two save points will appear, the right one of which will actually let you save. Race past some bats after transporting with the left save point, and you'll end up in Magus's sanctum.

Magus
Hopefully Frog has heal at this point, maybe even leap slash. Crono may very well have Lightning 2, and your third party member probably has some powerful attack fire or shadow magic depending upon whether it's Lucca or Robo. If you want to build tech points, running down the walkway and killing the bats is an easy way to do it, they should fall pretty fast to a multi-attack spell, and you can recover at the save point. Anyway, pick your party, equip them however you'd like, and get ready to face Magus himself.

Magus's gimmick is that he puts up magical barriers in such a way that only damage of that particular type can go through when that barrier is up. The barrier changes will be announced in the battle text, but a good rule of thumb is that the barriers are two way, if Magus is casting fire spells, only fire spells will work against him. He also changes barriers each time he's attacked. Frog with the masamune is always a good attack to try since it lowers his magical defense, and physical attacks can be used if you don't have magic of the particular type his barrier requires. Try to heal fairly regularly when your health gets low with Frog's heal spell ideally. When you read the text "Magus risks casting a spell!" it means that none of his barriers are active and you can hit him with whatever you want, but it also means he's about to cast the ultimate magic attack, Dark Matter, on your party. At this point he won't have very much health to go, so just stay alive and keep hammering him. When you finally finish him off, Magus will inform you that he only summoned Lavos, he didn't create him. Lavos will begin to wake up and you'll all be sucked into a time gate and disappear.

Challenging Lavos
If you go back and challenge Lavos at this point, you should get The Frog vs Magus Ending. Frog will duel it out with Magus and his henchmen without your help, and the two will finish things off with a battle at the top of the castle.

Also if you lose in the fight to Magus, you'll see a brief scene where he turns around and finishes summoning Lavos, and Lavos will make his trademark scream.