Etna's Secret is the fifth episode in Disgaea: Hour of Darkness.
The story begins with Etna telling Flonne a story about kicking someone "right there" (as the Disgaea DS top-screen Prinny hints us, it's a "man's soul"). Etna then finds an embarrassing photo of Laharl on the ground, and both she and Flonne burst out laughing. Laharl comes in, asking what all their laughing is about. Etna shows him the photo, and he is shocked. Etna mentions a note on the back, and Laharl reads it.
The note mentions a challenge for Overlordship, and should Laharl refuse, copies of the pictures will be spread throughout the Netherworld. Angry at this dirty trick, Laharl runs off to 'Jotunheim' to confront this demon.
His first challenge is taking on a bunch of Imps… who all say optimistic sayings, which is one of Laharl's weaknesses. During this challenge, Laharl's stats decrease (but they are restored after the map).
Laharl's next challenge is being surrounded by women with sexy bodies, which include KitCats and Succubus. (Here Laharl makes a note that flat-chested women have no effect on him, to which Etna and Flonne respond angrily back.)
The main villain, Maderas, then makes his appearance here, revealing that Etna was helping him all along, much to Laharl's anger who refused to listen to Flonne, stating he refuses to listen to the words of a traitor . Maderas then flees, leaving the team to fend against the sexy women.
The team manages to catch up to Maderas after that, but Maderas now throws both of Laharl's weaknesses at him. Sexy Succubi now start saying optimistic sayings, causing Laharl to scream in agony.
Vyers then appears, and asks how the team is doing. When Laharl tells him not so well, Vyers launches into a long motivational speech to get Laharl to realize an inner strength to help him overcome his own weaknesses. Flonne points out that Vyers "may have set the bar a bit too high for Laharl", to which Vyers responds that Laharl should just close his eyes and plug his ears. And when Laharl does, he no longer has any weaknesses. (as the Disgaea DS Top-screen Prinny says: Blindfold + Earplugs = Perfect Laharl)
Maderas now tells Etna to kill Laharl, or he will erase her memories. Etna then reveals that SHE poisoned the prince, but hated herself for doing so and working underneath Maderas. So she hatched a plan to "get out from under his thumb", using the prince as bait. And her plan has succeeded.
Maderas then turned to his Prinnies. However, they simply stare at him. Etna reveals she bought out those Prinnies a long time ago. With no more backup plans, the team fights Maderas.
After losing, Maderas immediately cries for mercy, and hands over Laharl's photo's, Etna's memory, and joins your team. Despite Etna having used Laharl for her plan and poisoning him, the two reconcile anyway. Flonne recognizes this, and decides to stay with them for a little longer.
One possible Ending is available here. You can get the Etna Heroine Ending by having at least 100 Ally Kills by the last map, Ice Queen, then choosing to kill Maderas.
Next Episode: Episode 6: Laharl's Challenge