My cat knows exactly what it wants when it yells at me. I just had to learn how to speak cat.
The meowing is just to get my attention. Once walk over to him, he'll walk over to the place he wants me to go. At that point I have to figure out what he wants me to do there, but it's usually food dish/water dish/couch for lap sitting.
Neither count thou two.
The part between the corners of the image. It's white and has grey and green blobs on it. You can't miss it.
Close, but not quite. PC stands for paper cassette, e.g. the tray you load the paper into. You're right about it referring to the paper size, though. PC LOAD LETTER just means "Put more letter-size paper into the tray."
Most of what you read online is incorrect, then, or at least misleading. Willpower isn't actually a stat in D&D. When your character asserts their will, they succeed at doing so, full stop. The save is for whether or not the character has an opportunity to do so.
What you have instead are Intelligence, Wisdom, and Charisma.
Intelligence saves are how much your character knows. An example here is illusion magic. Illusions are imperfect, and better understanding of nuance lets a character see an illusion as false, and then exert their will to disregard it.
Wisdom saves are about how much you can perceive and intuit. When someone attempts to control you, it's subtle, and the saving throw is about noticing that something is wrong. Once you notice it, your character exerts their will and shrugs it off.
Charisma saves are about your force of personality and sense of identity. When someone attempts to possess your body, they are attempting to change who you are, and is directly opposed by how strongly you believe in yourself, and how strongly you believe in who you are. Once you resist the attempt, you then exert your will and drive the spirit out.
You would simply say "The spellcasting ability modifier for this spell is Wisdom."
Wisdom is the stat that represents your willpower, your experience, and your ability to perceive the world around you. If something attacks your mind, it is most often resisted with Wisdom for this reason.
Realistically, it probably shouldn't be a spell, and it definitely shouldn't be this complicated. Spells used to have this level of granularity in earlier editions, and 5e specifically moved away from that for clarity and speed of play.
My recommendation is to decide if the person this item was created for (not necessarily the PC using it) is supposed to die or not when using it. If they are, then the item just kills them. If not, they fall unconscious at 0 HP, then suffer one failed death save as normal when the item detonates. Don't mess about with charging it with death saves or exhaustion levels, just have it do some damage.
One thing to mention: The saving throw type should match the means used to resist the effects.
Charisma represents your force of personality, your sense of identity, and your ability to interact with the world around you. This effect targets none of those things, nor can it be reasonably assumed to be counteracted by any of those things. Thus, this should not be a Charisma save.
Examples of effects with Charisma saves are possession (resisted by your own ability to be in control of yourself), Zone of Truth (resisted by your ability to interact with others), and forced planar travel (This makes sense with a longer explanation, but can't really be summarized.)
This should be resisted with Constitution. It withers the bodies of those trapped within it, so naturally should be resisted by how healthy that creature is to begin with. Dexterity is an option, too, but that's typically represented by effects that can be dodged with a split-second reaction without leaving your space.
Go for it anyway. If this girl is so shallow to reject someone for something stupid like that, she's not worth it and Anon dodged a bullet.
For real. Just because Putin is a Bond villain doesn't make every citizen of Russia one of his goons.
I agree that Meteion being built up more would have helped. Maybe even just having had references in a previous expansion.
Hell, we could have found out stuff in the First during Shadowbringers, since Meteion's song is what lead to the split happening in the first place.
I suppose in that respect, it does mean "I yearn!" but I've taken it to mean "Something's wrong!", with the nuance being that he'll want his food bowl filled even if he's not hungry or me on the couch even if he doesn't immediately want a lap.