Chaosmancer
Legend
When the Åsimar were missing from the Players Handbook, it seemed like Tiefling and Elf were the counterparts. This was a nod to the earlier Eladrin Åsimar. It is also matches their similar "lineage" design.
Maybe to you, but I never once saw the Tiefling and the Elf as thematic counterparts. At best you can say that they are mechanically similar, but that doesn't reference Eladrin either, since the eladrin have entirely different mechanics.
But now that the Åsimar are in, the Elf/Tiefling division is less elegant.
How? Just because the elf and the tiefling share a mechanical structure, and even that is a stretch because the second you step outside "cantrip, spell, spell" they don't share essentially ANYTHING, the Aasimar never changed any of that, nor are the Aasimar required to share a mechanical structure to be thematically opposed, and it is actually interesting that they do NOT share a mechanical structure BECAUSE of what that does for the thematics.