Actually, Huo Zhenting was killed by someone other than Bai Yunfei. He had been injured by Chu Yintian before being killed off by Xiao Qi. Plenty had actually been killed by Xiao Qi in that battle.

But a kill of Xiao Qi was essentially a kill of Bai Yunfei. So regardless, Bai Yunfei decided to step forward in response to Huo Zhenxiao. 

As Huo Zhenxiao said, the hatchet could no longer be buried. There could be no reconciliation nor compromise. If by chance the Wind Lightning School were to remain standing after today, Huo Zhenxiao could not be. To let him live would mean to risk the chance of a future retaliation against the Crafting School. 

Thus, Bai Yunfei decided to accept the challenge. It would rid themselves of a huge source of worry and allow him to see how strong he had gotte...