D&D 5E Little-Known Monster Facts

[Mouseferatu]

(I'm not a fan of modrons, but if I did use them, I would tie them into that same background. The modrons were the alien gods' first efforts at creating "reality infiltrators," when all they understood was that our reality consisted of three dimensions and inflexible shapes. The derro came later, as the old gods' understanding of our reality improved--but only to an extent.)

 

[77IM]

In one of my campaign worlds, hags and trolls are the same species; hags are the female of the species and trolls are the males.

 

[ccs]

Satyrs (male)/Fawns (female) cannot reproduce together. Instead they require a partner of some other race.
Females of these other races are abducted & kept by the tribe until the baby satyr/fawn is born (about 6 months). Once this happens the child is given to an adult fawn to nursed/raised along with her own & the mother is returned to her own kind/community.

 

[Blue]

Not 5e, but 13th Age which is d20 but the default setting is a bit different. They have the immense (mile+ tall) walking creatures called Koru Behemoths that follow this migration path to these springs of power to feed and have for Ages. They also have Living Dungeons that burrow up from the underworld. And finally in a war against the Dwarves, the Drow released a persistent poison that twisted people - it's where the Derro come from. Oh, and the Elf Queen (titular head of all of the types of elves, including the Drow) is said to have imprisoned the first Green Dragon.

These got all pulled together in my game. One player brought up his barbarian having beliefs similar to Shinto/animist ideas that everything, even a pebble, has a kami, effectively a spirit. (https://en.wikipedia.org/wiki/Kami) This blossomed into tying everything together.

Koru Behemoths weren't just the size of mountains, they were literal mountains that had for whatever reason decided they needed to roam, a rather un-mountain like thing to do. The madness/spirit-twisting poison that has infected all of the underworld was from The Green, but now kamis, otherwise natural spirits, that are coming up from there have been twisted into these living dungeons.

There's a lot of smaller places we work these Kamis into play as the reasoning behind things, and it gives a unique large scale feel and what is reasonable and expected can vary a great deal from a more standard fantasy society.

 

[dave2008]

I think a lot of people have probably removed the "colors" of dragons. I ran a campaign once where the "fire drakes" could breath fire or a cloud of poison and had acidic saliva. "Cold drakes" had the poison gas and acidic saliva, but no fire

 

[SkidAce]

Trolls in my games reproduce asexually, through budding. Due to their high mutation rate (which explains the huge number of different troll species), each troll is a different individual, not genetically identical.

Trolls are one of the races created by the Batrachi progenitor race in an attempt to create perfect soldiers. However, when the majority of Batrachi left Faerûn for other planes or the far future, trolls were left behind and eventually bonded with giants (whom they were created to fight). For this reason, many people mistake trolls for a type of giant.

Batrachi themselves split into several branches, broadly defined by the type of experimentation they mastered. One branch, which specialized in trans-dimensional magic, evolved into ethergaunts and spellweavers; another, which favored transmutation, migrated to Limbo where they modified the slaad Spawning Stone and reshaped the slaad races in their image; and yet another mastered psionic abilities and time travel and eventually evolved into mind flayers (doppelgangers, who were also created by the Batrachi, often follow mind flayers for this reason).

Impressive flavor.

 

[Mad_Jack]

I've included (and played) both original-flavor warforged and individuals that just used the warforged stats but had different origins in my games over the years, sometimes in the same game - one individual was an Awakened golem, another was a human soul placed into an animated statue, and the other one was actually a genius loci, the spirit of a particular battlefield who finally got pissed off after generations of wars were fought over him and grew an animated humanoid-shaped structure of plants and stone up through a set of plate mail from some long-forgotten battle, picked up some old weapons and gear and set out to share its displeasure with the local orc bands.

In one game, although it never actually came up in play and was mainly just my brain entertaining itself chasing thoughts around, I had it worked out that cloakers and similar creatures were originally descended from devil rays (the ixi-whatevers) who had made their way into Underdark lakes/rivers/etc. and then eventually evolved into land-dwellers. They eventually branched out into most of the other cave-dwelling things like piercers and cave fishers and even mimics.
Oh, and mimics were distantly related to doppelgangers - yet still close enough genetically to mate, which would have produced a creature I never quite got around to statting up that basically could change shape to look like just about any object or medium-sized creature.

 

[SkidAce]

Oh, and mimics were distantly related to doppelgangers - yet still close enough genetically to mate, which would have produced a creature I never quite got around to statting up that basically could change shape to look like just about any object or medium-sized creature.

/washes eyes out with soap...

 

[77IM]

True Dragons are all one species -- the 10 colors/metals are just the most common phenotypes. When True Dragons of different colors/metals mate, the offspring each resembles one of the parents in most respects, but sometimes has aspects of the other parent mixed in. So you might meet a red dragon, tinged with blue, who is immune to lightning and has a burrow speed, for example.

 

[BookBarbarian]

I'm also in the Dragons are one species category. Upon reaching maturity a Dragon will seek out a lair, and just as their presence shapes the environment, the environment shapes them. This results in the different breath weapons/immunities etc.