The way Holy City gets described in the novel and fanfics is, hostile to really talented people or 'calamity' or ' disaster victims', but is that really accurate?
First thing we have to agree is that Mo Fan and part of the Holy City have three points of contention, one Zhan Kong being the Undead Emperor, in Holy City's perspective undead no longer count as human and no matter how noble their actions are now in the future them being on the opposite side as humanity is inevitable.
This is quite frankly true, Zhan Kong himself has great trouble holding back his bloodthirsty side, Netherworld Queen says his decree is against the Undead's nature, even Zhan Kong's grandfather agreed with the mission and Mo Fan himself walked away, Mo Fan normally would have charged there and used Demon Element like when Feng Zhuolong was killed. But equally Michael's actions are not justified.
Yes, the Undead Emperor is in contention to be a Dark King but Humanity's core principle in dealing with Demon tribes was never extermination (unless absolutely necessary) but balance, Undead Emperor and Khufu should have been balanced, instead Michael did what was easy rather than what was right or better.
Second point is Ding Yumian, a disaster victim, the way it's set up Holy City's Heresy Judgement Court should be executing these people as they are supposedly dangerous. But do they? Qin Yu'er was banished to the top of Tianshan, an ice element Holy Land. HJC can't be unaware of what that means right?.
It's essentially a let off (compared to a death sentence) and seems more like a strategy to improve her strength and so on (a bad strategy, maybe). The only reason she was later captured was due to Undead Emperor killing plan. Wu Ku, Salan's underling, when he was spotted around Potala Palace the Heresy Judgement mage said that the mark on Mo Fan interfered with his tracking of Wu Ku (possibly using another mark). If there is a mark on Wu Ku it implies that Wu Ku was once captured and let off?
Ding Yumian is capable of managing herself under Dean Fu's care and by the time her identity is revealed Holy City doesn't have the time or the resources to deal with her.
Mu Ningxue isn't a true disaster victim (wiki says so), but I interpret it as she became one after perfecting her Ice Crystal Bow and unlocking her God's Gift (Forbidden level).
Third and most troublesome is his demon element, it's ruthless, it's strong and extremely connected to the Dark Plane which Holy City hates, and with reason.
The way the planes work is that Magic plane is constantly loosing resources to Dark plane, soul essences Night Amethyst which the Dark King likes and conversely Magic plane should also be plundering the Summoning plane (or at least capable of).
Unlike Zhan Kong's transformation where he and Khufu are contenders to be one of the Dark Plane's Four King's, upon completing the demon element Mo Fan is one outright. Which is good because he is crazy strong and will be at the level of High level Emperor at his peak and can give a hundred years of peace to the magic plane, but after his death will he become a Dark King like Wen Tai, that's probably what worries Michael's faction, I assume.
Also Forbidden Curse and Emperor levels are a secret only revealed at the Super level to grassroots mages or at the advanced levels to those with factions. Sort of explains why the National team thought the Elemental Evil Spirit in Sahara was one of the strongest creatures on the panet.
And Jiang Feng, who nurtured the Flame Belle should be an Elemental Evil Spirit ( i.e. a human possessing a certain element and died or nearly died in an Elemental Holy Land with great emotional fluctuations) rather than a pure Elemental Spirit.
Pseudo Emperor
Low level Emperor
Low - Medium Emperor ( between low and medium)
Medium Emperor
Medium -High Emperor
High Emperor
Plane Dominate? ( 4 Dark Kings)