when flowey gained six human souls, he had most of the control, but the souls were also capable of working together and rebelling against him, making him weak and powerless against frisk. When chara and asriel shared one body, their control of the body was apparently split equally. it seems as though the more souls that are inside the body, the more control over them the body’s original owner has. So why does flowey have so much power over the souls? why don’t all the souls have equal control over his body? that’s harder to say for sure. this is proven when asriel absorbs all the human and monster souls and recreates a monster body with his “godlike” powers the flavour text refers to the combined soul as “asriel’s soul”, not “asriel’s souls”. if something like that absorbs human and monster souls, all the souls combine into one.

The same rules seem to apply to “something that’s neither human nor monster”. each original owner of the soul gains the ability to control the body to some degree. When a monster absorbs a human soul, the two souls don’t reside separately within one body – they “combine”. How do souls work? what exactly happens to a monster when it absorbs a human soul? what really happened to asriel when he had the power of seven human souls? these are all questions that can be answered with one simple statement made in undertale.

Undertale what soul are you