Many of the bonuses in Soul Nomad and the World Eaters are obtained after getting at least one cycle in the game, which is easy to get early in the game if you decide to give your soul up in exchance to defeat Feinne the first time you face her. The Secrets are listed as followed:
Demon Path: Unlocked when you have at least one cycle.
The most extensive secret in the game, it is the second NIS game to have an alternate stroyline, the first being Disgaea: Afternoon of Darkness for the PSP. In the alternate path, known to fans as the Demon Path or Demon Campaign, this gives the hero the option to reject Layna's plea and go insane with Gig's power. The campaign is 14 stages, with the inability to go into towns, so you cannot use the Fight Edicts, Steal Edicts, and other Edicts that has effects outside of battle, the Strengthen/Weaken Edicts are the exception. The Demon Campaign is the only time you will hear the main character speak outside of battle, if you get the "bad" ending, winning the last battle in the alternate campaign.
Asagi: Beat Feinne the very first time you meet her.
One of the most difficult extra fights in the game, it is impossible to get this fight the on your very first cycle due to the fact you cannot power level yet, unless with the help of cheat codes. Asagi's stage will automatically happen when you beat Feinne, meaning you won't be able to have new Decors ready. This can be counteracted with the Edicts that allow you to get Decors during battle. Asagi herself is not difficult, due to her defense stats. However, she is tough: being on 1200 and having two attacks that can attack everyone in your squad. She is surrounded by twelve Gideons, who can also attack all units in a squad. Defeating this stage makes you restart, but gives you Asagi as a character, though she is treated more so as a class due to the fact you can get multiple Asagis each time you win and she can be deleted from the party.