Main change is that Deltarune has this wierd thing called PSI. Think of it as if it were Magic, but only certain individuals, more common in Humans, but monsters like Sans do have it, can use it, and they are referred to as Psionics, or Psychics. At base level, a Psychic can only move things around with their mind and use telepathy. Powerful Psychics like King Poo and the deceased couple Ness and Paula, along with Ness' elder cousin Ninten, can heal entire body parts, cause a tremendous amount of lightning to strike from their hands, and even shake stars to send small, 4 foot droplets of plasma hurtling towards the enemy. Other, more specific PSI users tend to practice only a handful of PSI, such as Sans and his powerful Telekinesis, PSI Beams (in replacement of Gaster Blasters because fuck those appearantly, they don't exist in canon of Deltarune as far as I'm aware), and Warpslip Ω, an ability thought to only be usable by Ninten as an Alpha PSI ability, can use far more powerful versions of weaker PSI or more situational PSI, s seen with Sans and his PK Beam Ω, which was thought to be impossible to perform before he performed it.

For those who aren't aware of Earthbound, why haven't you played it, the entire series is actually pretty fucking good, Undertale was inspired by the fuckers. Back on track, for those who don't really know how PSI works, I'll just give the three categories and and four...five power levels. Remember that certain PSI do not follow the rules of Power Levels, such as, before Sans cracked the code, Warpslide being only one power level and only ever being used to teleport short distances away from the enemy. The categories are Offensive, Healing, and Support. Offensive are all psionic abilities that are orientated towards harming your foe, utilizing emotions, energies, or brute psychic power to damage foes. Healing is anything that helps heal the body, either from things like Stone, Diamondization, Poison, or healing body parts. Assist is generally Defense, Ability Enhancers, Shields, and certain variations of signature PSI abilities (Ninten used to have Warpslip, Ness has PK Rockin', with variations called PK Origin and PSI Rockin', two twins, who live in Hometown, recently moved, named Lucas and Claus, have PK Love, and Kris has PK Prankin', subject to change, but that's the only thing I got about their personality other than they were somewhat creepy). Now, Power Levels. Alpha is the weakest level, then Beta is the second weakest. Gamma is basically the highest some go, but is the second weakest. Omega isnthe strongest any PSI user can use an ability at, unless you are a cosmic eldritch deity of hate and evil, then nobody can even comprehend your attacks, let alone take the attack without being basically the universe's chosen hero against said cosmic horror.

Not much else changes, except that Claus and Lucas join the Fun Gang, Ness and Paula are Kris' biological parents, Kris is a Psychic, weak at first and better off hitting things with their sword, but will get to the Lightning Power of his mother in due time, and there is no Snowgrave route. The variation is just Kris being consumed by the idea that their Psionic Powers could reach such levels as to kill gods, and basically abandons all reason and becomes a murderous maniac who electrocutes, incinerates, and freezes all creatures in his path, eventually leading them to become possessed by a piece of Giygas (the aforementioned cosmic horror) and Chara is just out of the picture now because fuck them, they backseated the Genocide Run and couldn't kill Giygas even with a timeline reset. If Chara is evil, then Giygas has mastery over them because he is basically the Incorporeal God of Psionic Abilities, Malice, Hatred, and pure and unbridled Evil. Luckily, that is also an alternate timeline to the canon Deltabound AU.

am calling it.. deltabound.

its a deltarune tbhk au..