Nurgle comes from the Warhammer 40K universe, he is described as being the lord of plague or the god of diseases, decay, and destruction. I will, however, take away his god like attributes, and true to make nurgle into an advanced alien race.
Appearance and behaviors
The nurglonians are said to look like fungus covered humanoids, who Simultaneously have the appearance of rotting flesh. The rotting flesh and body covered fungus like appearance comes from the fact that these aliens are categorized as plantoids. The appearances do vary, with some looking like they have pustules, and hives filled with insect like creatures, which is suggested to be some form of symbiosis. The height of said species ranges from 6-7 feet to even 8-9 feet, and have heads that look vaguely similar to the plague doctor masks, this has arisen a theory that the common plague doctor mask was inspired by these species, but there is little to no evidence to back this up.
As a species, they tend to keep to themselves, but do show a passive outlook towards other species. They believe that rot, decay, and pestilence lead to growth and the formation of new life.
These species are fairly intelligent, enough to the point of making worlds and creating new life. They will go from galaxy to galaxy, taking and making new diseases to spread across any habitable worlds. Generally looked down upon because of this act, they will occasionally make entire worlds and develop an ecosystem that revolves around rot and pestilence, where trees are covered in lichen, bugs infected with many blights and diseases, seas and lakes flowing with infection, mold infected grounds, and many many more.
When given the opportunity, these creatures will generally try to adapt any lower form of intelligence into their species, and try to make them adapt to their own beliefs without trying to cause any anger or hatred. Many worlds that previously had life, had gone extinct due to such drastic additions of diseases.
Other than their creepy and overwhelming beliefs, they generally try to aim for peace.
It is speculated that these aliens might have all transferred their consciousness into a new body, discarding the old ones, this theory arisen from the fact that their DNA is comprised of various other creatures DNA. The aliens have a considered a single planet sacred, scientist believe that the reason for these aliens caring over a single planet above all others is because this planet is covered in a living parasite that is capable of processing and creating new diseases.
Could such creatures feasibly exist, if not, then why?