They noticed that something was very, very wrong - that the very air was full of malcontent. That there was something sick and vile slithering just out of their vision.
It was only when they found Blooky that they knew what.
Their sibling, their twin, mangled. A hole through their chest and expression - oh gods. Blood spattered the little area Miss Toriel liked to hunt for snails in. Blooky left earlier to find these snails, to make friends.
But now all Blank could taste was the Snail pie they had earlier as it came back up. All they could see was the viscera and the pieces of their sibling scattered in a place they all thought was safe.
Stars, were they wrong.
Hapsta, baby Hapsta, was holding them and they didn't know when that happened. Didn't know when they had managed to get back to their feet.
It must have been Hapsta's doing.
They couldn't look at him.
And Maddie was gone.
They faintly remembered her scream of anguish when they came upon Blooky. Remembered the rage and the bile and the determination in her eyes.
But now they were in Miss Toriel's arms and sobbing into her freshly-laundered apron. The both of them barely managing to tell her who - what - they had found.
Blank could still taste the pie.
Maddie didn't come back.
They waited.
Miss Toriel had to go look for her. Look for the Monster responsible for taking her children away from her. She didn't tell them that part, but Blank could see it in her eyes. She was strong. Stronger than they knew they would ever understand. She would be safe. She had to.
They couldn't lose a mother again.
They couldn't lose any more family.
Their patience paid off in a morbid fashion, for just outside their door (oh gods, why did Hapsta go look with Miss Toriel? Why did he have to see what was left of his sister?) was their missing cousin. Strewn about like so much confetti.
It was Hapsta's turn to fall apart.
Blank held him as he screamed.
Miss Toriel ushered them back inside, told them to wait, and went down the hall - down the stairs to the Ruins door. She had to see. Had to check that no one had broken in to harvest the Human souls.
Blank refused to die like this.
They refused to be weak just like the first time.
So they armed themselves. Took the fire pokers from the fireplace and stood back-to-back with their baby cousin. No one would be able to surprise them.
And then they waited.
And waited.
And waited.
And wondered how much more their family would have to suffer.
"Children, come here. We have to leave."
Miss Toriel's voice beckoned them both downstairs and neither of them dwindled. Miss Toriel swore to protect them and she would. Blank believed that much. They trusted her that much.
But what awaited them down the winding hall from the stairs was not their adoptive mother.
It was a neat little pile of dust and a purple apron.
Blank didn't feel anything.
The weapon in Hapsta's hands clattered to the floor. Blank turned to see tears well in his eyes, to see that soft face turn to anguish.
To see a vine shoot out from the darkness and wrap around their little cousin's neck.
To see their little cousin yanked upwards. To see his fingers claw at the vine tightening around his neck.
To see, with one easy jerk of the vine, their baby cousin stop struggling.
Laughter rang out through the confined space and Blank only felt a hot dread eating through their heart. They dropped to their knees as numbness overtook them and the creature that consumed their family made its appearance.
Of all of the things they expected - of all of the faces they gave this Monster - they were not expecting a simple golden flower with a smile sharper than a knife.
"Howdy, friend!~ Looks like you're the only one left!
"What? Too stupid to speak? That's okay; I'll do all of the talking!"
Hapsta was just a baby, even though he hated to be called that. He was just so small compared to the rest of them. So young.
"...can you imagine what it feels like to be replaced by a bunch of whiny little crybabies? The four of you just moved in without a care in the world..."
Maddie didn't deserve to die like a brute. Her brashness didn't deserve to be the nail on the coffin. Her heart was in the right place, wasn't it? Hapsta needed his big sister and they needed their tall cousin.
"...and it's a real shame too; just imagine what power four Human souls would give me! Can't do anything with these..."
Napsta: their twin, their other half, their missing piece, their good. Would they die the same as them?
"...oh well!~ I suppose this wasn't a total waste! You babies were a little fun to play with."
And Miss Toriel... Their second mother. She took them in with no deliberation. Looked at their skin and their souls and treated them as equals. As her own children...
"...so, since I'm feeling generous, I'll let you choose how you die! What'll it be, friend?~"
There was an expression they heard once... Spoken of only in hushed tones and longing.
"Bury me standing up because I've been on my knees my entire life..."
"What? Well, it's your funeral, pal."
".....but I've only just learned how to stand..."
A question burned in their mind. A question they knew they didn't want the answer to. A question they craved and have been asking their entire life, but only now were they given a face to ask it to.
"Why?"
"Weren't you listening, idiot? Because you were all in the way!~ But if you're asking why you're still alive when they're all dead, then you should really be counting your lucky stars! You were supposed to go first!"
Blank didn't know when they got back to their feet or when they had gripped the fire poker in their hand. This wasn't like them. This was crackers.
The flower smiled and reared back its vines. It was mocking them and they knew it.
"Tell you what, friend. Since I'm in such a good mood, I'll even let you take the first shot!"
Blank screamed and swung the weapon like their life depended on it. And it didn't, really. They knew they were going to die. They knew they were weak. They knew that they were nothing without their family supporting them.
"Is that really it? Okay, my turn."
They wanted to give up.
Hapsta's lifeless body hit them and they tasted bile. His body jerked around by a single marionette's string.
They knew there was no point in fighting like this.
The vines were covered in thorns. How did they not notice before?
They wanted to lay down and die.
The creature threw them around like a doll. Up and down and from vine to vine.
They wanted it all to stop.
It just kept laughing. Kept taunting them. Kept dangling poor Hapsta like a butcher's wares.
They got what they wanted.
"Well, that was boring."
Blank was the first one to awake. The first one to burst into tears.
They could still taste the blood. Could still feel that welcoming numbness.
Blank was the one to beg their family to stay with them.
The one to ask Miss Toriel what happens when a Monster dies.
The one to learn that dust is all that's left while they were cradled in her arms, pressed against her beating heart, surrounded by their living family.
Blank was the first (and only) one to notice that things were the same, and in that sameness there was death just outside their door. Lurking and waiting for a mere moment's reprieve.