My head is ready to explode!

So, Nacht had a twin brother who looked exactly the same as Nacht looks like now?!

Nacht's "true appearance" was this, before he joined the Black Bulls

That's why Jack the Reaper said that he remembered a "different Nacht"

I believe that the reason Nacht hates Yami so much is because, it was Yami's fault that Nacht's twin brother, Morgen, died

Maybe this mission was Morgen's last mission he ever went with Yami

What do you think? Why do Nacht hate Yami so much? Why did he changed his hairstyle and made the same as his younger twin brother?