If you end up being unable to properly finish the hack(/get to the later chapters) before International Hack Release Day, you can end the game a few chapters early by having that earthquake that Lyon foresaw Rocks Fall, Everyone Dies (Emblem) the party/world.
Alternatively, if you are on schedule to complete the hack, you can make that early/bad ending happen once you reach X cumulative turns across all chapters.
The Symphones are present, but they’re green and steal your kills/droppables/chest loot/heal EXP. Some of them use rescue staves to mess with your positioning/momentum.
Also, just to screw with the player even more, throw in KFPs. Luna weapons + giving enemy Devil backfire chance is excellent enemy design. Ch12 was already enough of an RNG fest and the rest of FEU should be subjected to it.
na turn him from sage into a (green) Necromancer and force Ewan to not find a hiding spot if Ewan dies he turns into a (red) Necromancer getting a new inventory of two Fenrir tomes and with a berserk staff and Physic BUT if Ewan survives he becomes a unit in your army with a basic flux and heal.