The Starry Elder Evils of DnD
DnD has a handful of eldritch horrors that are/live within stars in its lore. The most well known is probably Hadar given that there's spells named after it. But there are others and I feel like talking about them.
Acamar
Acamar is described as a black star that consumes whatever gets too close. It's pretty obvious from this alone what kind of star Acamar is. It's a black hole. It's a hungry Elder Evil hellbent on consumption. Now why would anyone worship such a creature? Good question! My guess would be some misguided effort at keeping it fed to try to keep it away, or perhaps its worshipers see it as a cleansing force. Either way, its specialized Star Spawns, the Maws of Acamar, are certainly vicious.
Caiphon
Caiphon the Dream Whisperer, the Purple Star. As the title suggests, Caiphon is described as a purple colored star. It's also said to lend aid to those who beckon it, especially those who are desperate and feel rejected by the gods. But Caiphon almost always has a wicked price, and calamity eventually falls upon most who seek its help. Purple is a rare color in stars, however Type-O main sequence stars can appear purplish, so I believe that's what Caiphon is. It's also easy to see why people would turn to Caiphon. It's willing to help when all else fails. In my opinion, Caiphon genuinely believes it's helping. I don't think it intends for harm and calamity. It's just an immensely powerful eldritch being and doesn't realize that taking 10 years off someone's life as payment is kind of a shitty thing to do. It also seems to be associated with amoebas and music with alien tones and dissonance.
Delban
Delban, the Star of Ice and Hate. Not a pleasant entity to deal with if the name is any indicator. It is a bright white star usually only visible in winter. It is described as being a cold and hateful creature. Given the description, I think it's safe to guess that Delban is a White Giant star. Unlike real stars though, it's burning with cold plasma. Worship to Delban I can see being a similar situation to Acamar, an attempt at appeasement. Interestingly, Delban is mentioned in the Curse of Strahd module, as a small piece of it is within Barovia.
Gibbeth
Gibbeth, the Maddening Star. It is said to be an utterly unknowable green star. It's a creature so dangerous, that even knowing its name is a hazard. Interestingly, some flavor text from some 4E spells suggest Gibbeth was wounded or "slain" some time in the Material Plane's early history and that it's infuriated by this fact. It also behaves much like the classic concept of a cognitohazard. It it not only dangerous to know, but it WANTS to be known. Keeping the hazardous nature in mind, I think it's appropriate to compare Gibbeth to a pulsar or neutron star. As for cults, well the fact that it twists anyone who knows too much about it, its cults could be a completely supernatural effect as opposed to people choosing to revere it.
Hadar
The infamous Hadar. The Dark Hunger. Hadar is described as a cinder-red star that is barely visible in the sky. Additionally, the spells named after it often feature black tendrils. It is said to be a dying star and consumes matter in an attempt to stave off its death. Keeping this in mind, it's easy to assume Hadar is a Red Dwarf star, but I think it's more like a Brown Dwarf. A star that is either nearly dead or failed to properly start burning. They are extremely dim, only emitting a small amount of red or purplish light but otherwise appearing brown or black. The idea of feeding and empowering an entity may be the appeal of worshipping it, or much like Acamar its cultists may see it as a cleansing force.
Khirad
Khirad, the Star of Secrets. It is described as a beautiful blue star that shines brightest when calamity is about to strike. It is a purveyor of forbidden knowledge and secrets of all sorts. It isn't hard to see why a person would want to revere it. Anyone who seeks knowledge could be drawn to its divining power. I believe Khirad is a Type-B star of some sort. Exact size category doesn't matter, just some kind of blue star. Interestingly, Khirad is another one of the starry Elder Evils to be featured in Curse of Strahd.
Nihal
Nihal, the Serpent Star. A nasty Elder Evil described as a red star (though confusingly, sometimes green). Some say it's not a true star, but more a tear in reality full of worm-like creatures. And worms are definitely a recurring theme with Nihal. Even its unique Star Spawns are known as Serpents of Nihal. Star type for Nihal, much like Khirad, isn't as clear cut. Most likely though it's some form of red star. Whether that's a Red Giant or Red Dwarf, well that's up to interpretation. As for those who may worship the Serpent Star, perhaps they revere the process of decay and see Nihal as a cosmic version of decay.
Zhudun
Zhudun, the Corpse Star, is the final entry here. It's described as a "blank faced" star that can bestow prophecies as well as command the dead. Quite the grim creature, but given its ability to restore life fully, it's easy to see why a person might turn to it in desperation. I believe Zhudun is a White Dwarf star, as that matches nicely with the idea of a dead star with a blank face. Along with Delban and Khirad, a fragment of Zhudun is featured in the Curse of Strahd module.
There are of course other Elder Evils within DnD lore, including a couple more starry ones, but these guys have the most info. I think they have a lot of fun potential in games as warlock patrons or as antagonistic forces!













