Era
Middle Ages
When you first enter Magus's Lair, it's virtually empty. There are a number of NPCs in either of the side hallways, but nothing will attack. Once you've explored both halls and return to the entrance, Ozzie will show up and Monsters begin to appear. Despite his threat, you don't actually have to defeat every Monster in the castle.
The eastern hall leads to Flea. Running into the NPCs you see will trigger battles. The battle with "Flea?" is actually against a modified Juggler. It will counter the killing blow by eliminating one Character's MP, which can be annoying since the real Flea fight follows immediately afterwards. Flea's status ailments are annoying, so be ready to use Heals when necessary. When Flea starts counterattacking with The Stare, be careful.
Slash resides at the end of the western hall. You'll first have to defeat a group of Decedents, but normal attacks will make short work of them. Slash has two forms. In both cases, Physical attacks and Techs are your best offense. He is more dangerous with his sword. Defeating him earns you that sword, the Slasher (a nice upgrade for Crono), as well as a save point.
With both Bosses defeated, a teleporter (appearing as a save point) appears in the entrance hall. Through there, you will fight through a gauntlet of unavoidable battles. Sorcerers are the most annoying foes here.
After speaking to Ozzie, you'll reach the first trap room. Avoid the guillotines and collect the Treasure in the first room, and Ozzie will run again.
On the outer stairs, you will be forced into combat if you touch a Roly. Descend one of the short ladders to let them pass if you want to avoid fighting. If you do fight, be aware that Jugglers alternate between Physical and magic vulnerability each time you hit them.
Following that, you'll reach Ozzie's pit trap room. Even if you've memorized the correct route, fall in at least once to collect the Treasure in the pit. You'll fight a half-dozen Decedents the first time you fall in, but after that you'll only have to deal with the Save Points. There are four, one on each side of the room. Some are enemies, one is an actual save point, and the last will teleport you back up to the pit room. The enemies don't take much damage, but they only have 10 HP each. In my experience, the enemy Save Points tend to be across from one another, so if you hit one, try the adjacent points first. Once you reach Ozzie, no more pits will open.
The next outer stairs aren't as easily navigated. Outlaws have a nasty combination counterattack with Jugglers, so either hit them hard enough to kill them in one shot, or defeat the Jugglers first. Following that sequence, you'll enter two consecutive gauntlet hallways. You can avoid the fights in the second by walking around the statues instead of between them.
The fight with Ozzie is literally a joke. Just keep attacking the targets other than Ozzie and eventually you will be victorious. A save point and a teleporter appear after Ozzie is defeated. The save point is on the right.
I would recommend putting Lucca in the party when fighting Magus, so you have access to the three basic Elements. Whenever he uses an elemental spell, he becomes vulnerable to that Element. If he uses an Element you can't counter with, just attack him physically until he changes his barrier. Other Elements will not harm him. The Masamune will lower his magic defense, however. You will take a lot of damage in this fight, but remember that all of Magus's most powerful attacks are counterattacks, at least early on. Using a Barrier will help defend a Character from his spells.
Once Magus "risks casting a spell," go to town with whatever powerful attacks you have, regardless of type. X Strike is effective as always. Magus will eventually cast ✩DarkMatter, dealing up to 250 damage to each party member.
The eastern hall leads to Flea. Running into the NPCs you see will trigger battles. The battle with "Flea?" is actually against a modified Juggler. It will counter the killing blow by eliminating one Character's MP, which can be annoying since the real Flea fight follows immediately afterwards. Flea's status ailments are annoying, so be ready to use Heals when necessary. When Flea starts counterattacking with The Stare, be careful.
Slash resides at the end of the western hall. You'll first have to defeat a group of Decedents, but normal attacks will make short work of them. Slash has two forms. In both cases, Physical attacks and Techs are your best offense. He is more dangerous with his sword. Defeating him earns you that sword, the Slasher (a nice upgrade for Crono), as well as a save point.
With both Bosses defeated, a teleporter (appearing as a save point) appears in the entrance hall. Through there, you will fight through a gauntlet of unavoidable battles. Sorcerers are the most annoying foes here.
After speaking to Ozzie, you'll reach the first trap room. Avoid the guillotines and collect the Treasure in the first room, and Ozzie will run again.
On the outer stairs, you will be forced into combat if you touch a Roly. Descend one of the short ladders to let them pass if you want to avoid fighting. If you do fight, be aware that Jugglers alternate between Physical and magic vulnerability each time you hit them.
Following that, you'll reach Ozzie's pit trap room. Even if you've memorized the correct route, fall in at least once to collect the Treasure in the pit. You'll fight a half-dozen Decedents the first time you fall in, but after that you'll only have to deal with the Save Points. There are four, one on each side of the room. Some are enemies, one is an actual save point, and the last will teleport you back up to the pit room. The enemies don't take much damage, but they only have 10 HP each. In my experience, the enemy Save Points tend to be across from one another, so if you hit one, try the adjacent points first. Once you reach Ozzie, no more pits will open.
The next outer stairs aren't as easily navigated. Outlaws have a nasty combination counterattack with Jugglers, so either hit them hard enough to kill them in one shot, or defeat the Jugglers first. Following that sequence, you'll enter two consecutive gauntlet hallways. You can avoid the fights in the second by walking around the statues instead of between them.
The fight with Ozzie is literally a joke. Just keep attacking the targets other than Ozzie and eventually you will be victorious. A save point and a teleporter appear after Ozzie is defeated. The save point is on the right.
I would recommend putting Lucca in the party when fighting Magus, so you have access to the three basic Elements. Whenever he uses an elemental spell, he becomes vulnerable to that Element. If he uses an Element you can't counter with, just attack him physically until he changes his barrier. Other Elements will not harm him. The Masamune will lower his magic defense, however. You will take a lot of damage in this fight, but remember that all of Magus's most powerful attacks are counterattacks, at least early on. Using a Barrier will help defend a Character from his spells.
Once Magus "risks casting a spell," go to town with whatever powerful attacks you have, regardless of type. X Strike is effective as always. Magus will eventually cast ✩DarkMatter, dealing up to 250 damage to each party member.