After finally reaching Upover following a long journey through Wyrmtail, Wyrmwing, and Wyrmsmaw, you must climb the Magmaroo to meet Greygnarl.
The Magmaroo - L1
Go northeast from the entrance, then continue east and finally south. There is an exit to the outside where you find a blue chest.
Go back inside and head northwest until you reach the stairs to the next floor.
The Magmaroo - L2
Head southwest across the bridge, then go northwest and walk across the lava to find a chest that contains 1500 gold coins. Go back toward the south, then walk past the stairs to find a chest in the southeast corner of this area that contains a seed of defence. Then go back and go up the stairs.
The Magmaroo - L3
Go north to reach a set of stairs leading back down to L2, where you can access a red chest containing a Mini Medal. Go back upstairs and go south to the exit.
Outside, go west and head south when you can. There is a red chest there that contains Saint's Ashes. Keep going west to get to the stairs leading to the next floor.
The Magmaroo - L4
Go to the left and there are some stairs leading to an upper platform. You can go past these stairs and walk on a walkway under the platform, but it just leads to some pots that you can break for treasures.
Now go up those stairs to the upper platform, then head west and down the stairs. Go south and then east to reach a red chest that contains a CURSED Hades' Helm. Go back to the west and walk past the stairs that you came down. You will reach another set of stairs. Go up them, then go north past the stairs leading to an empty upper area. Keep going north until there are some stairs down to the dirt path. Get onto the dirt area and go north to reach the stairs to the next level.
The Magmaroo - L5
Go south and walk past the stairs leading up. There is an outdoor room on L5 at the far south where you will find a chest that contains Safety Boots. Go back inside and go up the stairs.
The Magmaroo - L6
Go south and then outside to reach the summit.
The Magmaroo - Summit
Make your way around the path, picking up the blue chest's contents on the way, then go into the area in the center.
The Magmaroo - Greygnarl's Lair
After meeting Greygnarl, you will have to fight him. Use Dragon Slash if you have it. He attacks with Blinding Light, Fire Breath, and physical attacks.
After you defeat him, Greygnarl will refuse to help. Leave the area, then use Zoom to get back to Upover. Notice that you can reach the Magmaroo summit using Zoom.
Looks like the Gittish Empire has decided to make problems for Upover. Talk to the guy in purple armor near the entrance to Upover. You will have to fight a Fright Knight and two Stenchurions. Afterward, peace will return to Upover for now.
Go up to the cave that leads to the Magmaroo and talk to the woman there. She'll tell you to take some Drunken Dragon to Greygnarl. She will show you the stairs leading down to the storeroom. Go down those stairs, then go into the room and talk to the guy standing next to the vats. He will give you a keg of Drunken Dragon.
Greygnarl will only see you if you're alone, so Zoom to Stornway and drop off anyone else who is in your party. Then just use Zoom to return to the Magmaroo Summit.
Go up and talk to Greygnarl. If you aren't alone, he won't talk to you, so drop your friends off at Patty's Party Planning Place in the Quester's Rest Inn in Stornway if you didn't before.
Give Greygnarl the Drunken Dragon. He will give you a Gittish seal. Then Barbarus will attack. Greygnarl will want to give you a set of Dragon Warrior Gear, but an Aggrosculpture will attack before you can get it. It's not too tough. Once it's gone, you will get the Dragon Warrior Gear: Dragon Warrior Helm, Dragon Warrior Armor, Dragon Warrior Gloves, Dragon Warrior Trousers and Dragon Warrior Boots.
Equip the five items of Dragon Warrior Gear listed above, then talk to Greygnarl. An animated sequence will begin. Afterward, you will find yourself imprisoned in the Gortress.