Etna Mode

Etna Mode is a bonus feature found in the remakes Disgaea: Afternoon of Darkness ,Disgaea DS and disgaea pc. As the name suggests, it features an alternate storyline focusing on Etna rather than Laharl. A similar mode, named Axel Mode is present in the Disgaea 2: Cursed Memories port Disgaea 2: Dark Hero Days. For some reason the mobile gaming port of the sequel doesn't have online play like the original game ports do.

Story
The story starts off as usual, but once Laharl gets up, he shouts instead of speaking calmly, which is what probably prompts Etna to shoot instead of putting away the gun. Thus, she kills Laharl. Without the prince, her plan of pitting Laharl against Maderas to regain her memories is ruined. She first attempts to make the Netherworld believe the prince is still alive by sticking a pair of antennae on a Prinny, but most demons including Maderas and Vyers see through the paper thin disguise. She then attempts to retrieve her memories from their hiding place in the Sea of Gehenna, but is stopped by Maderas who almost destroys her memories. Vyers shows up unexpectedly, stops Maderas, and convinces Maderas and Etna to battle for the memories in an all-out duel. Etna manages to retrieve her memories before fighting Maderas, who is killed by Vulcanus. In the end, Etna's remembers her promise to keep Laharl safe and sheds tears for killing him, but we later learn that he was merely unconscious.

Episodes
Etna Mode contains 4 episodes:
 * Episode 1: Super Dimensional Etna
 * Episode 2: Space Detective Etna
 * Episode 3: Chronicles of Etnarnia
 * Episode 4: Chronicles of Etnarnia (Cont.)

Unlocking

 * At the title screen, highlight the "New Game" option, then press Triangle, Square, Circle, Triangle, Square, Circle, X. (X,Y,B,X,Y,B,A on the DS or Switch. And I, J, L, I, J, L, K on the PC) If you entered the code correctly, you will hear Etna's voice.
 * On the mobile phone ports of Disgaea 1 Complete, you do not need to enter the code, it's automatically unlocked.
 * Alternatively, successfully complete the game after reading Etna's entries in her secret chamber. To enter Etna's secret chamber, press the two secret buttons in Laharl's Castle. The first button is behind the throne. The second button is inside the skull on the counter in RosenQueen's store. After both buttons are pressed, go to the room where Longinus, Ghoss, Gargo and a randomly-named prinny are usually found. Press X in the corner behind the prinny to reveal the door. If the player uses this method instead of the cheat code, the enemies will be much higher in level in the next cycle if you choose to play Etna Mode.
 * The player must read all entries BEFORE the final chapter and if attempting to enter the secret chamber during the final chapter a Testament will be awarded, which is the sign that Etna mode will be available after the ending of the current playthrough.

Other information
Etna Mode for the PSP and DS is the only mode in the entire series known to have a stage in which an enemy has an ability learned from another source. (Episode 2: Stage 2. Enemy: Female Healer. Ability: "Slumber." This is originally a monster ability inducing the Sleep status ailment.)