Actually, the Junwu Empire did maintain an embassy in Beiyan. Feng Xun had already contacted them earlier, but since Huyan Yichen was a local, Feng Xun decided there was no need to involve the embassy staff.
The battle between Jun Linyuan and Gui Qulai was not taking place inside the arena.
Their duel had been set at the Summit of Beiyan.
Chapter 152