[Before being chosen]
{Eggman and Metal Sonic}
Dr.Eggman was observing the creation of an army of robots in his lair. (Whichever lair you want, space lair, island lair, ocean lair, etc.)
"This army of badniks will surely get rid of that blue pincushion and his rodent friends!"
Eggman laughed then it broke into a series of coughs.
Metal Sonic, who was standing nearby, rolled his eyes.
Orbot and Cubot entered the room, struggling to hold the Eggmobile.
"Boss, we just finished polishing and drying your Eggmobile to the point of perfection." Orbot said.
"Yeah and we cleaned it too!" Cubot said, using the simple synonym, not knowing that Orbot just said the same thing.
"Yeah, yeah, that's great, just set it here." Eggman said, not paying much attention, as he was watching the creation of the robots.
Orbot and Cubot set the Eggmobile next to Eggman.
"This army of robots is my best YYYEEEEEEEEETTTTTTTTTT-" Eggman screamed the last part as he was plucked through a portal, along with his Eggmobile and Metal Sonic.
{Knuckles}
Knuckles was leaning against a tree next to the Master Emerald.
"Ahhh." He sighed in a relaxing manner.
"Nothing like a lazy day on Angel Island."
Or so he thought.
"What the HEEEEEEE-"
Knuckles screamed as he was plucked through a portal.
[After being chosen]
{Eggman and Metal Sonic}
Eggman had just listened to the few words the Master Hand had said.
"Ho ho ho ho ho! Luckily, I just had my Eggmobile enhanced! This should be a piece of cake! And if, no, WHEN I get the wish, I can easily be rid of that blue pineapple!"
Eggman laughed.
He pointed to Metal.
"And! Even if I somehow manage to lose, you and I have the same wish! So we have double the chances! Not that we need them, I will surely win!"
Metal moved his head side to side in a 'Yeah Yeah, whatever.' motion.
Eggman finally seemed to notice that Knuckles was there too.
"You? What are you doing here? What's your name, Noodles?"
{Knuckles}
Knuckles listened to Master Hand's words.
"One wish? I can make sure that nobody ever steals the Master Emerald ever again!"
Knuckles crossed his arms and snickered, his iconic laugh.
Knuckles then looked to Eggman.
"My name is KNUCKLES." He said in annoyance.
"And don't get so confident, I'm definitely gonna beat you!"
He said and pounded his fists together.
(And...done. That took a bit. Also, I didn't find it necessary to give bios for Orbot and Cubot, as this should be the only post taht they are involved in. Anyway, here's the info:
https://sonic.fandom.com/wiki/Orbot (Orbot) https://sonic.fandom.com/wiki/Cubot#Villains (Cubot) )