"Peasant! Fancy meeting you here!" Red Son yells, practically spitting in your face.

The place you came upon was the... red light district, Kabukichō. VERY out of pocket for Red to "visit".

"Wait- you're wondering why I'm here? Because Mei wanted to meet me here so we can... uh. Battle! Definitly NOT hanging out!" Mei doesn't come here. It's quite obvious actually, she pranked him. So, Red is here for.. pretty much nothing.