Brines are an universal species. They are half demon, half vampire. This makes it so there isn't a possibility of a Brine hybrid because you need both the vampire and demon genes to be considered a Brine. Also there's the fact that Brines are technically a type of hybrid anyway.

Across the universes, not including Minecraftia, there is a small hierarchy. Brines generally live in small groups or villages, so there is a leader, some guards to protect the village, and the everyday Brines.

Brines have a nasty reputation. They are known to be bloodthirsty and often go on raids to destroy nearby human villages. Both their demon and vampire halves create an actual thirst for blood. They either torture victims, sometimes to death, and lick up the blood (demon) or bite down and drink the blood from the side of the victim's neck (vampire). They prefer human blood over any other type, including the blood of an immortal.

Brines have fangs, like a vampire, that are mostly retractable. This allows them to blend into society and spy on the humans. The fangs extend when a Brine is bloodthirsty or ready to attack.

Brines typically have a lover or partner for life. They aren't limited to the opposite gender as Herobrine himself is bisexual. They also aren't limited to the same species as many Brines have a human partner. If their lover is threatened, the Brine quickly turns from vicious to desperate, begging the attacker to stop. Brines emit a loud wail if their lover is killed. They weep for a few days before seeking revenge on their lover's murderer. It is rare for a Brine to search for a second lover after the first is killed, though not unheard of. This is because most Brines go into some type of depression after their lover's death. Sky only had one lover, though Herobrine has his second lover, Devin.

Brines are natural enemies of Aetherians, making Notch and Herobrine's relationship unheard of. Aetherians hunt down Brines to keep the humans peaceful and fruitful. Sometimes an Aetherians will spend their entire life hunting down a single Brine.

Herobrine is well known among Brines, being the only Brine that is a god and part of a prophecy. Brines have a lifespan like that of a human, Herobrine being the obvious exception.

Most Brines have a fire-based magic, mostly due to their demon side. The fire they create is based off the color of their aura.
Ex: Herobrine's aura is white, so his fire burns white.

Brines are well-suited for a hot climate, especially dry biomes known to catch fire. Herobrine designed the Nether to suit himself, as it is hot, dry, and filled with victims to torture as he wishes.

Haha how's that for a species's description? It'll be going into Forever Immortal in a min.