A topic I haven't seen discussed enough is how Kris is able to separate the soul from their body. The answer is simply because, They are a chosen keyblade wielder, and using the keyblade they got from maleficent they are able to separate their own soul from their body turning themselves into a Heartless and a nobody right? I mean it makes sense. Even the prophecy calls them the hero. But why would they do this? In the very first chapter of the game Ralsei says that the soul is the very culmination of Kris's being. In that case how come the soul comes under our possession? Why is Kris able to influence our decisions if we control the very culmination of their being? 

The answer is simple.

Kris is known to despise being a human and would rather be a monster instead, and we know that Kris may have violent tendencies that they don't like. In order to solve this, they and catty summoned maleficent using their voodoo demon magic, but catty was a pussy so she ran away. Maleficent then gave Kris a keyblade and in exchange Kris would give her Noelle holiday since she is a princess of heart (duh). 

This causes them to grow distant from themself trying to escape who they are, to "stop being kris", and allowing them easily separate themselves from the soul. In other words, while Kris in the game is not meant to be a stand in for the player we are still meant to represent Kris we are their heartless they're actual desire, but by acting as what the true Kris wants instead of what the body wants, and Kris as the nobody, acting in the way they know they wish they could act. Like this we can foretell the rest of Kris's story line. By the end of the game Kris will either form their own heart (soul) and finally be free from being Kris or will come to accept their actual soul(us) and then we will merge as one and truly become Kris Deltarune.

Like this everything else becomes so obvious. The dark world is actually just kingdom hearts and the clash between the light world and darkworld is just talking about the keyblade warriors clashing against xehanort. The reason Noelle does our bidding in WR is because Kris is actually another clone of Xehanort and norted Noelle. The opening of a darkfountain is just opening a door to darkness

Kris (no soul) is a nobody and we (Kris no body) are their Heartless.