Talk about an anti-climatic ending! Nobody gave you the mission to defeat the Rogue Alliance. At most, one character said that "if", "just in case" you want to do it, then his knowledge will be useful to you.
And although everybody said the Rogue Alliance is very dangerous, the only crime they committed throughout the whole game was just kidnapping the wife of a merchant (apart from trying to kill you for trespassing).
Map of the Rogue Alliance headquarters. Red diamonds = pit traps Red tiles = fixed battles
Labyrinth: it is a tradition of Adventure games to feature a pure maze as a final dungeon. Indeed, the first part of this dungeon is a square-shaped 10x10 labyrinth, free from monsters, but featuring several pit traps. False walls allow to get past this section avoiding any pit.
The magic ogres: after the initial square section, the party will navigate a few passages and reach a large hall. A magic teleporter-door sends them to the secluded quarters of the "magic ogres". They set the rules: one character only. There are no random encounters, just one fixed combat.
The final area: after you encounter the rhyming skeleton, visit the "hero's closet" before you open the other door. When you open said featureless door, the final battle against the Rogue Alliance will start.
