Gnoll

In the continent of insulae, they roam in small packs, mostly unorganized and scattered. They all follow yeeonghu though. 

In agrea, there doesn't seem to be an exact time when the gnolls started to spread like wildfire, but they had a sudden boom across the rolling hills of the valley of the sun. Before the gnolls weren't very advanced, but numerous. They suddenly somehow became bigger, stronger, faster, and flooded the plains. Pushing back any sun elves into their cities and catching a stalemate with the city. After awhile there is stories told of the gnolls bringing the dead back to life, other gnolls with no hearts undead, fighting on. Skeletons of dead comrades roaming the plains. Currently, after several decades, they are still in a deadlock with the sun elves.

At one point the Gnolls attempted to invade New Dawn. They are a technologically inferior creature before the landing of New Dawn and were known steal what they couldn't make. They stole many boats and attempted a water invasion. Once they landed there was a force of several different tribes lead by a powerful head huntress. Within an hour the head huntress was vaporized a long with many of her forces and the tribes broken.

More then big mongrels

Gnolls will very depending on whether they've taken the rights or not. Yeeonghu average height is about 5'11" for Males and 7' females. Sometimes the chosen of yeeonghu grow to large sizes able to eat horses in easy bites. Those who don't take the rites, Heretics, are an average height of 4'11" for males, and 6' for females. Yeeonghu average weight is 170 for males, 260 for females. The Heretic Average Weight is 130 for males, 200 for females. All gnolls are spotted and furred with a large ridge of hair from their head down their back. They look like bipedal hyenas.

Of beast and bone

The Gnolls are a barbaric race and vicious followers of the demon lord of butchery, Yeeonghu. Most Gnolls serve their god and their tribe, going through a ritual of passage called the rites of mutarada. During this ritual they take a special drug to open their mind to their innate connection to yeeonghu, going on a vision quest. This vision quest leads them through a demonic nightmare land where you eventually join the hunt with Yeeonghu. Once they make their first kill during this hunt the gnolls solidify a connection to their god. Their gods only command is to eat and destroy. Leave ruin in the wake of the hunt. Some gnolls refuse their rites, those gnolls are outcasts and never exposed to the link. Not having an open link to yeeonghu, they sacrifice a part of themselves, but the reward is freedom.

For pack gnolls, the average male members of the race stands at about 5'11", though gnolls are relatively lean for their height, weighing in usually between 130 to 150 lbs. The females average a standing between 7' and 7'6", though female gnolls are relatively lean for their height, weighing in usually between 280 to 320 lbs. and the race cuts an impressive visage. Female and Male gnolls that escape the influence of yeeonghu, tend to be 1 foot short on average, rare as they may be. Gnoll skin is a greenish-gray, and their furry hide is light or dark brown marked sometimes with spots or stripes. Many gnolls also have a dirty yellow to reddish-gray crest like mane that stands on end when a Gnoll is angry

To be or not to be a pack gnoll

Gnolls of Yeeonghu:

A pack gnoll is trained towards warfare and the hunt. Any individual gnoll doesn't matter only the will of the pack leader. As such pack gnolls defer to the leader of any particular group. The leader tends to be a female gnoll. The main quality that matters in gnoll culture is strength. Cunning is valued, but cunning doesn't swing the club. Good leaders tend to have both qualities.

Each pack has a hierarchy among the females and males separately, the males always being beneath the females, often do to a strength difference, but also do to tradition. Any conflicts are decided by combat... no guards... no one to help you... if you loose the victor claims the body of the loser, often consuming the heart believing they'll gain their strength. Literally the strong consume the weak. The threat of death at any slight to a superior is often enough to keep most gnolls in line. The body left behind after an internal combat is then resurrected in service of the pack as a witherling. Witherlings have low intelligence and obey the commands of the gnoll shaman that resurrected them from the dead. Often some tribes will look for opportunities to pray on the weaker tribes to make them into groups of witherlings under the command of a greater gnoll shaman, lead by a female gnoll leader.

In addition to other tribes, the gnolls live for the hunt and often commit warfare and butchery against other races to satiate their lust. Typically small villages will be left empty without any bodies to bury. Often survivors, many of them children hidden away in floor boards and dirt holes, tell tales of the gnolls eating all the flesh leaving only bones. When the bodies are picked clean their shaman raise undead skeletons, still slick with blood. No prisoners have ever been found or bargained for. In kind, no adult gnolls have been captured, but summarily put down like rabid animals. Gnolls of Yeeonghu are currently not accepted anywhere in civilized places.

Heretic Gnolls

There are some observations on gnolls that have been raised outside of a pack or that have left their pack. The first is that often gnolls that abandon their god are wracked with paranoia and pain. They believe the pack is always on the hunt for traitors to the cause. The wild gnolls believe the heart of a traitor is especially delicious and treated like a delicacy. The pain they feel comes from being raised that might makes right. Gnolls raised in a pack try hard but fail often to fit in more civilized cultures. This often leads to them becoming criminals and outcast. Gnolls taken as young pups usually fair better. They learn the ins and outs of the culture they are raised in. This leads to those gnolls taking on the customs and morals of those who have raised them. Last is that all gnolls have a zeal about them, a fervent fury that comes out in battle like a frenzy. They also, like dogs, feel the need to have a pack. In this way, many heretic gnolls form packs, and occasionally you'll find a gnoll or two that has formed a 'pack' with a few other races.

It is rare that a gnoll finds a pack of gnolls that doesn't believe in yeeonghu, but it's not impossible to find one.

Gnoll traits.

Age. 
They can live around into their 70's, but often don't live longer then 35 due to how often they kill or are killed.

Racial Beliefs (Alignment).
You could call them opportunistic and follow pack hierarchy which makes them tend to be neutral evil. Heretics tend to be whatever alignment of who raised them or what their circumstances provide.

Size.
You are a Medium sized creature

Bite or claw.
When you make an unarmed strike you may bite or claw your opponent instead, changing the damage from bludgeoning to slashing. 

Speed.
30 feet

Languages.
If you're a gnoll, you know common and speak gnollish Abyssal. Gnollish is written in abyssal and it's a sub-dialect of abyssal. If you're a heretic, you speak common, and may change out gnollish abyssal for one language of your choice.

Gnoll heritage. 
On creation choose a heritage gained from being part of the pack or escaping it.

• Yeeonghu Rampage. As a Yeeonghu When you reduce a creature to 0 hit points with a melee attack on your turn, you may, use a bonus action to move up to half your speed and use a Bite or Claw attack.
• Heretic Vigilance. Once per a long rest, as a reaction to being attacked you can roll a 1d4 (before the out come is determined.) you may add the result of the d4 to your ac until the beginning of your next turn.