Said other guys all have interesting Landscapes and lifestyles…
Nurgle’s idea of Paradise is pretty much the Paradise sought after by Poison Ivy.
Yes Mortarion is the Final Boss of that Game… If he is bringing Poison Ivy’s aesthetics to a Sector you know that Nurgle is just another Poison Ivy… And yes Poison Ivy can control Fungus! She commands both the Green and the Grey due to being(in her own words) Mother Nature! She is also immune to Bacteria and Viruses so she probably has control over them as well.
Poison Ivy is Nurgle at her core!
As for the other Chaos Gods:
Khorne’s corruption is simply staining the inside of Buildings with Blood and causing Blood to rain down from the outside! Khorne wants Blood, Molten Metal and Skulls!
Tzeentch has a Crystal Labyrinth which has been summoned directly into the Materium to the prisoner’s chagrin! The rest of his Crystal Realm which includes a huge Eye hasn’t been summoned though although considering they are clearly the property of specific persons one has to make a deal with them first!
Slaanesh has interesting Domains: Fields straight out of a painting that even smell of Paint with the Rivers being made of Perfume… Buildings made of Flesh… Yes… very interesting and that’s just the areas outside the Seven Circles of Seduction!
First Circle holds Golden Statues, Silver Trees and Grass, Gold Mountains, Roads paved with Emeralds, Rubies and Sapphires and floating in the Air are those same Gems!
Second Circle is a Sea of Wine with Giants holding large Platters connected by Bridges containing the Finest Foods!
3rd Circle is a Golden Field with Slaanesh’s Claw-handed Girls dancing.
4th Circle is a plain of Ash filled with illusions of praise
5th Circle is a Serene Forest filled with pools to reflect on Pride
7th and last Circle is a Beach next to a Sea of Perfume where one can rest till you become dust
The Palace of Slaanesh is protected by Slaanesh him/herself whose form is infact that of a child… The Grey Knight who came to challenge him/her was caught off-guard and pledged loyalty to Slaanesh upon seeing his true form despite managing to pass the 7 Circles of Seduction!
To any saying a Chaos God like Slaanesh is unbeatable: Warhammer 40,000: Chaos Gate - Daemonhunters as already noted is making Mortarion a Final Boss for Grey Knights despite one assuming he is beyond such a defeat as a Daemon Primarch!
Yes he respawns yet even despite this him losing to an army of Grey Knights with nothing less than what I’m assuming is Zerg Rushing is not what one expects of him!
Inquisitor had us defeat Fabius Bile and now Daemonhunters is having us take on a Daemon Primarch! It’s only a matter of time until we take on the weakest of the Chaos Gods! Slaanesh’s childlike form won’t protect him from the most paranoid, child-hating soldiers! First chance we get we banish him from whatever World he and his Realm has been summoned to or stuff him into a cell!
Of course he might corrupt his opponents who beat him into violently throwing him him into a cramped cell filled with spikes that’s dumped into boiling water just because he likes the sensation of being a prisoner in a cramped cell filled with spikes that’s dumped into boiling water!
Making the Marines desire the sensation of creating the cruelest most sadistic prison for Slaanesh might allow Slaanesh to drive them to more vile acts as they boast of their victory over a Chaos God!
Note: If Slaanesh ever becomes a Final Boss please make Him/Her into an Anime-esque Konata Izumi(from Lucky Star) Ripoff(complete with Long Hair) so his/her imprisonment(because the Imperium know that killing him is impossible) is all the more comedic!
Orcs have a Fungi Forest and as for Dark Eldar and Craftworld Eldar: Dark Eldar infested parts of the Imperium look like Silent Hill-esque Cult Areas…
I have no idea what Craftworld Eldar, Tau or Necron areas look like and have only seen an Exterminatus’d Tyranid Planet so I have no idea how good those areas are or whether we should root for them!