A/N: Rest assured that, while the beginning seems depressing, it actually is humor, if of a rather macabre flavor.
Harry knew that the dementors would be bad news, but he had hoped that they would at least be held back by the foreign guards that Dumbledore had hired. Without his wand, even Harry couldn't hold back a dementor.
But the guards could do things without wands. Harry had seen Hatake Kakashi gut a werewolf with a lightning-encrusted hand. He'd seen Uzumaki Naruto clone himself in the hundreds during battles. He'd seen Haruno Sakura punch craters in fits of rage. He'd seen Uchiha Sasuke grow wings like a demon. He'd seen Sai bring paintings to life.
Now? Now he saw them under the dementors' influence. He saw Kakashi standing stock still and gazing blankly into the distance as blood seeped from beneath that bandana. He saw Uzumaki Naruto fall to the floor and scream as his eyes bled red and his clawed hands tore at his abdomen. He saw Haruno Sakura weep and grip her head as unknown memories flooded it, more shaken by her teammates than by the dementors. He saw Uchiha Sasuke break his suave façade and start yelling and sobbing and shouting and screaming incomprehensibly. He saw Sai… be… unaffected?
"Oh my." Sai was looking at his teammates with an expression that seemed vaguely concerned. "This reaction doesn't fit in with anything I've read other than trauma triggers."
"The dementors." Hermione's voice wavered. "They feed on emotions. They suck out every happy thought and memory, and they make you feel like you'll never be happy again. And if you let them get close enough, they, they—"
"Oh!" Sai smiled at her, that fake, disturbing smile. "So they lack emotions of their own? Or they bottle them up?"
"I guess it's… possible?" Hermione sounded confused.
None of them were fast enough to stop Sai as he jumped down, walked up to the closest dementor, and held out his hand.
"Hello, my name is Sai. Would you like to join me for some art therapy? I also have a copy of the Kama Sutra, Jiraiya edition, and—"
Harry never did quite hear the rest of Sai's words as the dementors died from starvation, Sai having accidentally sucked up all the emotions they had taken into himself and caused them to implode.
It was a very strange day.
A/N: I am not continuing this. I just wrote it because I needed to get out of my writer's block.
Oh, and remember that this is complete and utter crack that makes no sense in any universe. So yes, there's a five-man team. Yes, it's AU. And yes, Sai resembles his early Shippuden self. Please don't complain about me going off into something that could never happen in canon.