After deeper understanding of researches, I have reached a conclusion I could not understand at first, but once I saw it multiple times with further experience, it has been clear, further more than the water or the sky.
Frisk I canonically dead, speaking in canon aspects and facts.
Why do I say Frisk is dead? Very simple question, let's check the facts:
- Closed eyes
- Neutral expression
- Never talks
- Yellow skin color
This diverse fact aspects, are delievered from experiences of undead death and regeneration, a mutation of DNA through determination and magic, where magic flows from within actively even if Frisk isn't capable of using magic directly, and determination bonding the soul to the body constantly.
The closed eyes, the neutral expression, and the fact of Frisk never talking, are undead fact aspects. The tiredness brings someone to remain eyes closed and not have energy to focus on the surrounding or even talk. This also affects the expression, as Frisk isn't entirely themselves, which brings a neutrality with everything and everyone around, as careless as Flowery without adding anything else.
For the Yellow skin color, is a mutation of the DNA being genetically changed by the determination bonding along the magic actively flowing through the veins, and doesn't has anything to do with being dead or alive, as is a simple biological reaction to a genetical mutation.
This information has been proven after researches, mainly from UltSans himself, as suffers the same effects, but did not reach the levels Frisk did reach.
This fact aspects should not be confused with genocide determination, as is a completely different thing, same with the Pacifist/pure determination.