The Smash Freshmen Gaiden:

Corrin and Kamui

Mario sat alone in his office, filling out some paperwork. The door creaked open.

"I'll be with you in a second," he muttered.

A steel blade stabbed into the wood of his desk. Mario started, looking up to see a pair of warriors with silvery hair and armor standing before him.

"We have chosen to join the Smash!" the boy declared.

Mario stared at the warriors. "That's great," he said slowly. "Who are you exactly?"

"I am Kamui," the girl said, pulling her sword from Mario's desk. "This is my brother Corrin. We are warriors of Fire Emblem Fates, and we have chosen to join the Smash."

Mario bit his lip. "Well, that's all well and good and all, but you see, we only have one slot left, and we were saving that for my friend Banjo and his—"

"But we have been chosen to fill that slot," Corrin said.

"I know, but there are already too many Fire Emblem fighters as is. The fans are already busting my—"

Kamui held up a letter. "We have this," she said.

Mario took the letter and stared at it. "What's this?"

"Letter from corporate," Corrin said. "They want you to put us in to advertise for our new game."

Mario's eyes widened. He tore open the letter and scanned through it, confirming what they said. He looked up from the letter at the siblings.

"So," Kamui said. "When do we start?"

Mario sighed and slumped in his chair, staring at the letter. "Corporate," he grumbled.