I'll expand this to 1200 words while keeping your exact opening and closing lines intact.
At exactly three in the afternoon, Jelo, Atlas, and Mira arrived at Tongen's house.
The house sat at the edge of the academy grounds, surrounded by a wide open training field.
Tongen was already there.
He stood calmly in the center of the field, holding the same small red ball in his right hand.
Jelo stepped forward slightly.
"So we're really doing this again?" he said.
Tongen nodded.
"Yes."
Atlas cracked his neck slightly.
"Same rules?"
"Almost," Tongen replied.
The three students looked at him carefully.
"You still have to take the red ball from my hand," he continued. "But this time… I will not hold back as much."
Jelo sighed.
"I knew the restaurant thing was too good to be true."
Mira crossed her arms.
"I knew something was suspicious."
Tongen raised the red ball slightly.
"You may attack together."
"Begin."
Atlas moved first.
