So, based on their abilities, lizardfolk (humanoid reptiles) should be a more prevalent race in my setting than they actually are. When I say they're overpowered, I mean they have everything to expand their territory and resources, which is pivotal in a world plauged by naruto-running zombies with Wolverine-regeneration.
General characterstics:
- Height: 170-190 cm on average
- Extreme regeneration: all lizardfolk are able to grow back any organ (except the brain in most cases), albeit not at the speed zombies do. They don't drop their tails (obviously)
- Cold-blooded: they are lizards
- They've a human lifespan
The three subspecies:
Nile-crocodile folk:
- Ridiculously strong bite force
- The largest (consistently 190 cm) and strongest
- They are also the slowest (on land), though that isn't saying too much
- Their osteoderms provide decent protection from many physical attacks, even weaker firearms
Komodo-dragon folk:
- Jack-of-all-trades, master of none
- Stronger than the Asian-water-monitor folk, weaker than the Nile-crocodile folk, slower than the Asian-water-monitor folk and faster than the Nile-crocodile folk
- Average height 170-180 cm
- They have a potent poison, secreted from glands in the lower jaw
Asian-water-monitor folk:
- They're incredibly fast and agile
- Tall, athletic build
- They are good climbers and are often arboreal by choice
- They are also good swimmers
- The smartest of the three sub-species
- 180 cm on average
Just to give you a point of reference, let's take these three friends from one of my drafts:
- Pondering friend, an Asian-water-monitor folk, who built a treehouse by himself just to get away from annoying friend, that's why he left the ladder out. He likes ranged weapons and camouflage, the two things he can beat annoying friend with.
- The annoying friend, a Nile-crocodile folk. He uses a nicely-made club (I think the design is a Polynesian war club). It's advised to wear top-quality riot gear when engaging in combat with him. Pondering friend hates taking him on on one-on-one duels, since those club strikes always break his guard, which he considers outrageous and unfair. Pondering friend also regrets teaching him the German suplex.
- Mysterious friend is the peacekeeper between pondering friend and annoying friend, going as far as breaking up fights. Pondering friend also regularly coats his arrows with mysterious friend's poison.
You might be thinking, "Why not just throw Cocytus in to give those three a very bad time?" If you were to do that I'd finally have enough unspent CR to balance that encounter with a Bertholdt nuke.
Basically, I need a biological weakness that can't be solved with a hand-knit sweatshirt (body-temperature maintenance) or similar low-level technology, and would hinder all three species in combat, based on the already established facts (the list items). However, this weakness shouldn't make them too weak; defeating them still needs to be a bit of a challenge.
What would be the most likely weakness? (it can only be one oversight in their physiology)