Any suggestions? It sounds like they were intended to be "relics of a bygone age", almost like "dire serpents" if you will.
Well, since you asked...
An enormous python with a body as thick as a small tree. When the snake opens its mouth and hisses, it reveals that its bone-crushing coils are the lesser of its weapons, for the python's gaping jaws have venom-dripping fangs the size of stilettos.
Giant fanged pythons are survivors of an ancient lineage, descended from an age when reptiles ruled the world. These serpents are only found in jungles, where they prey on any living creature small enough for them to swallow (a regular-sized specimen can swallow a tapir or bison, the biggest fanged pythons are said to be able to swallow elephants).
These snakes are easily identified by their eponymous fangs. Their coils are not quite as muscular as an ordinary giant constrictor snake, but the extremely toxic venom in their fangs more than compensates.
Fanged pythons are excellent climbers and powerful swimmers, who will often be found up a tree, or in or near a river. Like any predator, they hunt wherever their prey congregates, so are usually encountered around game trails, drinking holes, and salt licks. These snakes hunt humanoids as readily as animals, even slithering into villages or aboard riverboats to snatch a victim.
One unusual trait of fanged pythons is that they're more social than most snakes. During the breeding season they form mated pairs who cooperate to guard their nest and its eggs.
[Do we want to give a number and value for the eggs?].
A typical giant fanged python is between 40 and 50 feet long and weighs about 4000 pounds.
COMBAT
A giant fanged python's favorite tactic is dropping on prey from above, typically from a tree or cliff. They will also ambush opponents by hiding in water or undergrowth. Fanged pythons move fast for a snake, and will often chase after prey who escapes their initial lunge.
A fanged python tries to constrict as many opponents as it can handle, while using its poisonous bite against whichever foe is giving it the most trouble. These snakes are confident in their lethality, so will fight small groups of man-sized opponents simultaneously (such as adventurers). If they face an opponent too strong to easily constrict, such as a rhinoceros, a fanged python tries to inflict a few poisonous bites, then slithers away to wait for their venom to take effect.
Their weapons may be deadly, but fanged pythons are as keen to avoid death or injury as any serpents. They would much rather ambush weaker or unprepared victims than risk a straight-up fight against opponents of matching power. These snakes will readily slither away ff an encounter turns against it, taking whatever route seems the safest. Typically, an escaping giant fanged python will climb a tree, dive into a river, or disappear down a burrow or snake-pit.