Among the largest grouping of tieflings in Arethil, that of the Asmidarl Tieflings of Malakath, the primary tongue spoken is the Red Speech. But for those tieflings who are not of the Asmidarl, who reside in Liadain or Epressa, theirs would naturally be the local language of the people amongst whom they live.

The Red Speech can perhaps be harsh on the ear for those unused to it. One might perceive in its sounds and cadence a subtle sense of dread, of invocation, even of malice, all of which possibly exacerbated by the appearance of the speaker himself/herself.

Tone plays a firm role in the Red Speech, and often denotes hierarchy like teacher and pupil, commander and soldier, master and slave.

Perhaps more so than any other race does variety of features define the tieflings. But commonalities do tie them together, and despite the wide diversity they are all recognizable as a distinct whole.

The one trait every tiefling has in common are horns. All tieflings have horns of some kind which protrude from their head. Short or long, thick or thin, straight or curved or spiraling, the variations are abundant, but all tieflings have them.

Tails are another trait. Near ubiquitous so as to almost be defining like horns, almost all tieflings will feature a tail—usually, but not necessarily, pointed. Tail lengths can also reach impressive lengths, and tieflings have fine and dexterous control over their movement.

Now less common than tails are hooves and digitigrade legs. Some tieflings will exhibit legs and feet akin to humans, elves, orcs and other such species, but some others will be possessed of the aforementioned hooves, and with this will come certain advantages and disadvantages (better running, worse climbing, for example).

Skin color and its wide range also sets tieflings apart from other races. Indeed, in most cases a people will exhibit differing shades, but tieflings exhibit more than merely darker or lighter shades, but true color. Red is very common, alongside blue and purple just behind it, but pink and gray and white and black are also seen, and others still, the whole spectrum encompassed and halted only by rarity.

Other features, such as wings or tentacles, are not entirely unheard of, but are so rare as to not merit mention as common traits.

While tieflings by their nature can be anywhere in the world, what makes them stand apart from other adaptable races is their affinity for harsher lands. Where others might see desolation, barrenness, and unforgiving hostility to life, tieflings can very often with their arts both magical and natural turn these places into rugged homes, settlements, and even nations.

All tieflings have access to magic. An individual tiefling's grasp of magic may be so inept as to be negligible, and they might never use it, yet still magic they have. One can be "strong in the Tief" or "weak in the Tief" and all the levels in-between. Tieflings are not born of magic, however, as it is with, say, elementals, and they can survive even if cut off from their magic (though such a case may be uncomfortable).

By corollary, a tiefling's lifespan also increases with their mastery of the Tief. At minimum a tiefling's life expectancy will exceed that of a human's, though it will be lesser than that of a dwarf's. But with greater harnessing of the Tief within a tiefling's life can come to rival that of an elf's, or perhaps even beyond.

Among tieflings there is also the unique ability to control one's own fertility. As there is a natural curl to one's fingers and one must exert some control to straighten them, so too must tieflings, both male and female, will themselves to be fertile. Casual couplings are in consequence much more common. Furthermore, to bring a child into the world—and therefore to pass the Tief unto them—is a conscious choice for tieflings in a way unparalleled by other races.

In addition, there are no half tieflings. Tiefling fathers will always sire tieflings, tiefling mothers will always bear tieflings. Heritage of the Tief continues thus unbroken, its touch persisting, inextricable and undeniable.

For the history of the Asmidarl Tieflings, see "Asmidarl Tieflings" in the Sandbox wiki.

As for the history of other tieflings—those not of the Ascended King's heritage—it will by necessity be wide and varied. Other groups and settlements of tieflings upon Liadain and Epressa may well exist, created of different heritages. An individual tiefling, if not born as such but rather having become one through some touch of the Infernal, the Eldritch, or other means, will have an entirely personal history all their own, a heritage all their own, since they are the first of it. Mystery may even abound for those tieflings who do not know their past, their heritage, how they have come to bear the Tief; and answers to these questions may be found, or may forever elude them.

It is said in the words of an ancient religion that there exists eternal the Two spheres: the Primordial Dark, and the Light Everlasting. Ever does the one strive against the other, and each does the other bound, Light and Dark swirling and dancing in eternity. And along this shifting boundary springs thus the realm Material from the realm Spiritual, and in the Material are worlds made and life fashioned; and the very line between the Primordial Dark and the Light Everlasting runs through every beating heart. No higher freedom is afforded the soul but this: to choose, even against all adversity, in every hour of every day, that Dark or that Light.

And to the Power that exists in the realms Spiritual, shared among the Two, manifested in opposition, a name is given.

The Tief.