Hellfire Chasm is a new 10-level Soul of Chaos dungeon added in the Dawn of Souls release of Final Fantasy I. It is an optional dungeon, located among the various Dragon Caves. Access is granted once players have defeated the Fiend of Fire, Marilith.
Astute Final Fantasy fans might recognize the bosses contained in Hellfire Chasm, as they all previously appeared in Final Fantasy IV (not to be confused with Final Fantasy II). Players will need to run the entirety of the dungeon at least twice in order to see all four new bosses.
It is highly recommended that you save your game before entering Hellfire Chasm! It is also highly recommended that you do not save inside Hellfire Chasm, as once you enter, there is no way out except for defeating a boss.
Entrance Area
A lone elf keeps watch over the entrance area and notes that few adventurers will brave the dangers beyond the doorway. If you haven't defeated Marilith yet, you can't continue beyond this point. WARNING: Once you enter the nearby door, you will be unable to return to this area. Also, the White Magic spell Exit and Black magic spell Teleport will not function further inside! Enter the door when ready.
Basements 1-4
The basements are randomly-ordered from a set group of 8 different basement layouts.
Basement 5 (Boss Floor)
This basement is a fixed layout and contains no random enemies. Two of the four new bosses (Cagnazzo and Scarmiglione) reside on this level. Approach the flame and press A to engage one of the new bosses. Upon defeating either boss, the player may choose to proceed deeper into Hellfire Chasm or may choose to exit to the surface.
Cagnazzo
Located in the southern room on B5.
Scarmiglione
Located in the northern room on B5.
Basements 6-9
The basements are randomly-ordered from a set group of 8 different basement layouts.
Basement 10 (Boss Floor)
This basement is a fixed layout and contains no random enemies. Two of the four new bosses (Barbariccia and Rubicante) reside on this level. Approach the flame and press A to engage one of the new bosses. Upon defeating either boss, the player is forced to exit to the surface.
Barbariccia
Located in the eastern room on B10.
Rubicante
Located in the western room on B10. A treasure chest containing a Ribbon is located nearby.