Okay, of those, I've heard of "Merlin," and excepting Merlin were all created long after Dungeons & Dragons was. How exactly does that make an archetype?
Points for including Merlin tho, I'll concede that one.
In any case, it's all an argument of taste, which can't really be resolved, merely accepted or rejected.
-The Gneech
You and me both. 4e tieflings never felt like tieflings to me.
The random traits table in Planescape reflects much how I like tieflings. Each a unique being with no home. Many mad, many weird or just plain odd.
I adore the randomness and wild variety inherent in 2e/3e tieflings, but I really have a hard time viewing the 4e tiefling as remotely the same creature (and by extension the 5e tiefling as well). I look at the 4e/5e tiefling and I get a very 'Ceci n'est pas une tiefling' vibe at the very best.
I wouldn't remove the 4e style tiefling from the game, but I'd present it as one option among many (which is unfortunately not a courtesy present in the 5e tiefling). It's a shame to have lost that diversity (though it remains with Pathfinder tieflings, and that split is bound to be a headache moving forward with two overlapping audiences having very different expectations for two races named the same but being very different in execution).
Okay, of those, I've heard of "Merlin," and excepting Merlin were all created long after Dungeons & Dragons was. How exactly does that make an archetype?
Points for including Merlin tho, I'll concede that one.
Amusingly, at least to me, the idea of Merlin being the son of a fiend was a mistaken reading of the original material.
His father was a 'daemon', which in the usage of the early medieval era meant a fey-like being that lived in the upper air. (While some thought they were angels, it was pretty widely agreed that they weren't exactly fallen angels. And of course, some said the same of the fey too.)
In general, D&D tends to make "outsiders" rather more biological than I would like. Tieflings to me make more sense as offspring magically corrupted or influenced by fiends than otherwise.
(Also, just how do fire genasi get their start?!)
Half-dragons were either highly uncommon or rare, tieflings now a days are not. While they aren't common, they are around. It's like they have few numbers when compared to the other standard races, but actually seeing one is rather common. Tieflings and Dragonborn are the two poster children of 4th edition and moving them to some supplement would be an admission that they weren't as popular as Wizards wanted them to be. They should have had Tiefling/Aasimar in the DMG with the whole devil pact being one example of many variants of the race. They should have left ot up to the people to decide how they wanted to deal with the race. I know you can leave out whatever you like, but sometimes I like a bit of official cannon.As the name implies, genasi are most commonly sired by genies IIRC. They're not the offspring of pure elementals generally speaking (if ever; my genasi lore's a bit rusty).
Tieflings are also generally the offspring of half-fiends rather than directly demons or devils. The Races of Faerun sourcebook also indicates that their heritage can stay hidden for generations, so occasionally one just "pops" out of a seemingly human bloodline that a long time ago consorted with fiends. The same goes for aasimar I believe.
As for how biological fiends are in D&D, I kind of see your point but I don't really see it as any more fundamentally ridiculous than half-dragons. Shapeshifting, I believe, is generally involved in both cases.
Because Tiefling was an out-of-the-box option in 4e, and a lot of people played Tieflings.
With the new edition, they wanted to support that race out-of-the-box again.
Amusingly, at least to me, the idea of Merlin being the son of a fiend was a mistaken reading of the original material.
His father was a 'daemon', which in the usage of the early medieval era meant a fey-like being that lived in the upper air. (While some thought they were angels, it was pretty widely agreed that they weren't exactly fallen angels. And of course, some said the same of the fey too.)