Need Help To Choose Right Word For Translation

[InKoreaSouthHPJiwonAhn]

HP Pythia's attention is needed

In writing: https://www.templeofzeus.org/Physics_of_the_Soul.html

What does 'missing' mean in this sentence?
a) as if someone is missing b) something is deleted c) something has gone

I don't want to cause misunderstanding so I could need more answers to choose the right word for the translation.

 

[Ol argedco luciftias]

The part that is unknown, that we have no way to detect. We are only able to observe 1/10, so the other 9/10 is hidden and unknown.

 

[InKoreaSouthHPJiwonAhn]

Thank you so much. I respect your knowledge.