The Underworld fortress is the final stage before the Overworld. Your goal is to get to the room of Twinbellows, the boss of this fortress. Centurions will not be able to help you very much with this fight, so it is best to save your mallets for the other fortresses. On your way to Twinbellows' room, you will find many traps. Your enemy, the Eggplant Wizard, will appear for the first time. Locate the Shop, Hospital, and Hot Spring on the map. Check the route to the boss room and head for it. This is a large map, and you may need to use the scroll bar below the map to view all of it.
- You will start off near the center of the fortress. Take the door to the right to enter a blue Ganewmede room.
- Staying and fighting to collect points and hearts is optional. Continue to the next door on the right.
- Defeat the Kobils, but watch out for the Shemums that appear from the pots as soon as you pass beneath them. Collect the map if you wish, but it won't do you any good unless you purchase the pencil and/or the torch. The room to the right gives you access to a shop and the Hospital. Visiting them is optional. When you are ready, climb up through the top ladder.
- Wind your way across the platforms to reach the ladder at the top, taking out the Kobils along the way. Climb up to the next room.
- When it is safe to do so, jump up through the yellow platform, and advance to the left door.
- When you enter this room, it is a good idea to squat down so as to avoid getting hit by a flying Eggplant when you advance towards the Eggplant Wizards. Drop down to the floor and begin pelting them with arrows as soon as you can. The wizard closest to you will not be able to hit you, but keep an eye on the eggplants thrown by the farther of the two. Avoiding the eggplants is a higher priority than killing the wizards. If you get hit by an Eggplant, retrace your steps and make your way back to the Hospital as quickly as possible. When both wizards are defeated, enter the left door. It is not recommended that you visit the shop up above since the wizards will reappear when you return to the room, and you are most vulnerable to their attack when you are above them.
- This room is nearly identical to the previous room. Stay low to the ground until you drop down to the floor and can attack the wizards. Defeat the wizards and enter the left door.
- Wait a moment and watch the pattern of spikes until you have the timing down. Jump over the first spike box when it is safe and drop down to the ladder. Climb down to the room below.
- Quickly drop to the floor by falling down to the left. When you climb down the ladder to the room below, try to stick to the left side of the ladder.
- As Pit climbs down this ladder, be sure to press and hold as you drop, so as to reach the ledge on the left that is otherwise out of reach. Enter the door to the left. If you miss this ledge, you are going to have to cycle all the way back to a room near to your starting location, and retrace your steps.
- Fight the four Kobils here if you wish and take the ladder down.
- Drop down to the floor, fighting more Kobils along the way, and take the ladder down.
- When you arrive on the floor, first travel left to visit the Pool of Recovery. When all of you health is restored, return to this room and take the door on the right.
- Once again, wait a moment to analyze the timing of the spikes in this room. No matter what, do not miss the jump over the first pool of lava, it can be difficult to escape. Take a break in the middle of the room before proceeding past the next to spikes and taking the right door.
- Pass through the room of red Ganewmedes. The red variety is stronger than the blue and take more hits to defeat, but they are worth more points and hearts. Enter the room to the right, and be prepared to dodge more eggplants.
- Two Eggplant Wizards occupy two different platforms. Take care of the lower wizard first as it can threaten your safety if you try to attack the higher wizard instead. Once the lower wizard is defeated, attack the high one, and then proceed through the right door.
- This room is no different than the previous spike room. Cross over to the door on the right.
- Drop down to the floor and deal with the two red Kobils that you find here. Run over to the ladder and climb down to the room below.
- There are four red Kobil that you can contend with or ignore. Run into the right door to reach the boss of this fortress, Twinbellows.
Boss fight: Twinbellows
Twinbellows is not an extremely aggressive fortress boss. His fiery breath is more of a threat to Pit's health than his body. Twinbellows is not capable of attacking enemies that stand behind him, as the only time he turns around is when he has traveled the extent of the room and has no choice. Therefore, you can typically jump over him and attack him safely from behind. You may even manage to catch him in such a state that he cannot move. If this is the case, continue firing arrows at him so that he does not have a chance to recover and resume any movement.