There's not much to be said about the Bruthem. Other than sometimes living in marshlands, these animals are similar to hippopotami.
Except for the "heavily-armored and carnivorous" thing. So, basically a heavily-armored, carnivorous hippopotamus. With the same amount of aggressiveness.
These creatures dwell on riverbanks and in swamps, waiting patiently for prey. That patience pays off, however, as they have vast reserves of energy with which they will pursue prey.
Bruthem have few natural predators, save some of the sapient races, who prize their skins as armor. Treasure acquired when fighting a bruthem probably represents the creature's thick hide.
The Glimp-shell is a strange sort of pack animal, like a cross between an ox and a snail. These bipedal, shelled things are completely blind, but make up for their lack of sight with superior hearing and olfactory senses. Additionally, there is evidence that glimp-shells have psychic senses, forming an empathic bond with creatures whom they trust. Glimp-shells are prized for their loyalty, as well as the fact that they can carry heavy loads and never eat, instead absorbing ambient energy from their surroundings.
The following glimp-shell represents a mature specimen:
Older glimp-shells are more expensive, but are prized for their superior durability:
Finally, some breeders have miniaturized glimp-shells, breeding specimens small enough to accompany adventurers on dungeon delves:
A glimp-shell costs about 1,000 gp. Elders can go as high as 25,000 gp. Miniaturized versions cost around 1,800 gp (presumably, a hypothetical miniaturized elder would scale similarly, costing 45,000 gp). These costs can vary from place to place, as normal, but these are standard costs for mounts of these levels.
A glimp-shell's normal load is 450 pounds, heavy load is 900 pounds, and maximum drag load is 2,250 pounds. Their reputation as beasts of burden is well-founded.
Finally, there are the mysterious Xulg. The inscrutable xulgs are scholars with the ability to peer into other planes and dimensions. They have a great love of arcane knowledge, and will gladly pay for tutelage. Otherwise, they spend much of their time meditating, contemplating mystic insights and trying to push their sight beyond the physical. They have a natural ability to perform many types of scrying rituals without using components, but are always glad to learn other rituals. They will frequently barter with ritual scrolls and magical artifacts.
The xulgs are also skilled planeswalkers, and will sometimes help travelers with their innate Planar Retreat abilities. With adventurers being the murderhobos they are, though, many only encounter this power when they force the poor creature to retreat. Some even claim the large, pink eyes of the xulg can be used as material components in some scrying rituals (or as foci for some magical devices), but so far no one has been successful in recovering one (catching something that can plane-hop at will is hard).
The xulg depicted here is a potent magus with knowledge of several spells. Naturally, this creature would love to learn more.
In combat, a xulg may fight for a round or two, trying to scare off its attackers with a display of force before using Planar Retreat. Xulgs typically only continue to fight if somehow prevented from teleporting. They may, however, summon several vortexes to cover an escape.