After finding the Ninja village, you seek the legendary sword.
Make sure that you have at least five Rune Bottles and at least two Mystical Runes. Have Arche use only her fire elemental spells, and turn off Klarth/Claus's Undine, Sylph, and Gnome. You will want Cless/Cress to use his fire elemental skills, like Phoenix and Magma Rift.
Go into Freezekill and use the northern exit to find a church. Check the front door of the church to open it. Go in. Walk all the way up, then check behind the pulpit to open the door. Go in.
Go down the stairs. Open the chest to get a ?Helm, which becomes a Paladin Helm.. Then equip the Sorcerer's Ring and shoot the switch on the wall. Check the switch, then flip it. Exit right.
Go up, through the door, then down the stairs.
Use the Sorcerer's Ring to light the two candles, then go to the right and light those candles, then where the path splits go down and follow the path to light three sets of candles. Go back to where the path splits and go right to find the last pair of candles. From there, go south, go through the door, open the chest to get a ?Armor that becomes a Star Cloak, then go down the stairs.
Follow the path until you reach a statue. Use the Sorcerer's Ring on it, then push it UP, not left or right. Push it as far up as it will go. It will stop in front of the hole in the wall. Then go right and light the candles. Southeast from the candles is part of a wall. The door is in that wall. Go down through it and go down the stairs.
Follow the path, and when you see water, exit left.
It is worthwhile to get all of the treasure in this maze. But if you would rather not get it right now, then from the four-way screen that you start in, just go west twice, where you will find a Black Onyx, then go north until you are out of the maze.
If you don't want all of the treasure, but you do want a new spell for Arche, then from the start of the maze, go down and you will find an Armlet, then go west three times and you will find the Tidal Wave spell (which you should turn off for now), then go east, then north, where you will find a Black Onyx, then just keep going north.
If you do want to get all the treasure, then from the start of the maze, go down and you will find an Armlet, then go west and down, and you will find a Charm Bottle, then go north, then west twice and you will find the Tidal Wave spell (which you should turn off for now), then go east and north, where you find a Black Onyx, then go west and you will find a Silver Cape, then go east, then up and right to find an Aqua Mantle, then go up, then east twice to find a ?Book that becomes Ex Mortis, then go west and up and you will find a Silver Plate, then go down, then west until you find a Shield Ring, then go east and up, where you will find a room with stairs. Go down the stairs.
From the stairs, go down. If you don't have the Rare Shield, go all the way left to the far left door. Go through and get the Ankh Shield. Now go back the way you came, and go through the door to the right. Your way will be blocked by a chest that contains a ?Helm, which becomes a Star Cap. After getting the ?Helm, continue up then right and into the next screen.
Follow the spiral toward the center of the room until you reach the switch. Flip it. Now go up and take the path that exits right.
Then just follow the path down the two sets of stairs.
Follow the path, go up through the open door, then flip the switch. Don't go through that door yet. Instead, exit right.
Go up through the door and open the chests. The one on the left contains a ?Bow that becomes Gale Spread, and the one on the right contains Cute Mittens. Leave the little room and exit left.
Go left until you see an open door, and go through it. Step on the switch, then exit and go down the stairs to the left, onto the frozen water, and follow the path to the next screen.
Go up the stairs and through the door, then go through the door directly to the left, then follow the path to exit right.
Go through the spiral and flip the switch, then go back up and exit right.
Walk onto the ice, then go right and there will be a piece of the floor that you can walk onto to exit north.
Get ready for the upcoming battle.
Set Arche to only cast Fire Storm. Set Klarth/Claus to only cast Maxwell. It is best to cast the spells manually. Set Cless/Cress to use Magma Rift. Equip Klarth/Claus and Arche with Mystical Runes, and also Mint if you have an extra one. Equip Klarth/Claus with the Aquamarine Ring. Equip the Aqua Mantles on Cless/Cress and Mint. Arche should already be equipped with the Dark Robe. Equip Cless/Cress with an Armlet because he is likely to be stunned often. For the formation, put Arche and Mint on the far left, and Klarth/Claus just to their right. Have Cless/Cress at the far right.
Go up to the next screen. You won't be attacked in the room with the columns, so fill your food sack and walk around the entrance until you are all healed up. Use Orange Gummies on anyone whose TP is low.
First, cast Haste on Cless/Cress. Arche and Klarth/Claus should be casting Fire Storm and Maxwell as quickly as possible.
Cless/Cress should use Magma Rift as often as he can, but Cless/Cress should stay far enough away that Fang Wolf doesn't punch him.
You might become backed into the corner if you are not casting spells and using Magma Rift as quickly as possible.
It is possible to have Cless/Cress walk under Fang Wolf while he is jumping. This will allow Cless/Cress to use Magma Rift without getting punched, but Klarth/Claus and the others will then be vulnerable to Fang Wolf's punches.
Fenrir's Cavern, Part 2
Now you have the Vorpal Sword and a new long range skill: Soul Edge. Assign Soul Edge to Cless/Cress to allow him to master it as soon as possible. However, do not equip the Vorpal Sword yet, because it heals the monsters in this area.
Change Klarth/Claus's skills to use everything but Undine, Sylph, and Gnome.
Change your formation back to normal.
To exit the cave from the save point, go down, then left across the ice, then exit left, then go down through the second door, then go up the stairs, then follow the path, then go down twice and east three times, then go down and follow the path and go up the stairs, then go up through the door and follow the path up the stairs, then go up through this door, then go all the way left, then go up the stairs, then go down and exit left, then go up the stairs and go through the door, then go out of the cavern.