Bullywug

Bullywugs are amphibious, frog-like humanoids who thrive in many of the places ordinary folk don't. Due to their skin, they must stay constantly moist, and so they make their dwelling in rainy forests, marshes, and damp caves.
Bullywugs have green, gray, or mottled yellow skin that shifts through shades of gray, green, and brown, allowing them to blend in with their surroundings. They most often wear crude armor and wield simple weapons, and can deliver a powerful bite to foes that press too close.
  Bullywugs are often considered evil, due to their differences in values. A bullywug values size and strength, and constantly tries to eat as much as it can in order to grow. Power hierarchies are usually organised around the strength of an individual, and therefore its size. Their concept of posessions is tied to ideas of territory, which always belongs to the largest and strongest. Therefore, a bullywug will take whatever it wants from someone smaller or weaker than itself, and will do its best to convince those around it of how strong it is, in defence of any belongings or territory it might have.
Additionally, bullywugs are not brought up in a nuclear family, but instead hatch as the smallest and least important members of a large tribe. Finding and preparing food for the tribe is a shared responsibility, but it is not a communal activity, and the largest eat first.

Once individuals have established their strength, they will often develop an arrogant attitude and puff themselves up. This sort of strength persona is established for when physically fighting would be dangerous or to the detriment of both parties. They display their social strength by ordering their underlings about, and gaining the favour of those above them with flattery and obsequience.
One particularly notable bullywug trait is the obsession with extravagant titles, which display their strength and achivements to strangers easily.
In more intelligent tribes of bullywug, some recognition is given to the status implicit in having capable and loyal underlings. From this, there may be a subtle drive to train and equip the young of the tribe well, to encourage them to develop other skills (such as music or magic), and to make use of the benefits of contact with the mammalfolk.
From the Monster Manual:
A bullywug has two ways to advance among its kind. It can either murder its rivals, though it must take pains to keep its criminal deeds secret, or it can find a treasure or magic item and present it as tribute or a token of obeisance to its liege. A bullywug that murders its rivals without cunning is likely to be executed, so it’s more common for bullywugs to stage raids against caravans and settlements, with the goal of securing precious baubles to impress their lords and win their good graces. Invariably, such fine goods are reduced to filthy tatters through abuse and neglect. Once a gift loses its sheen, a bullywug lord invariably demands that its subjects bring it more treasure as tribute.
  Unruly Diplomacy. Bullywugs love nothing more than lording over those who trespass on their territories. Their warriors attempt to capture intruders rather than simply slaying them.
Captives are dragged before the king or queen — a bullywug of unusually large size — and forced to beg for mercy. Bribes, treasure, and flattery can trick the bullywug ruler into letting its captives go, but not before it tries to impress its “guests” with the majesty of its treasure and its realm. Struck with a deep inferiority complex, bullywug lords fancy themselves as kings and queens, but desperately crave the fear and respect of outsiders.
Amphibian Allies. Bullywugs speak a language that allows them to communicate over large areas by croaking like frogs. News of intruders or other events in the swamp spread within minutes across this crude communication system.
Simple concepts in the language are understandable to frogs and toads. Bullywugs use this capability to form strong bonds with giant frogs, which they train as guardians and hunters. Larger specimens are sometimes used as mounts as well. The frogs’ ability to swallow creatures whole provides a bullywug hunting band an easy means of carrying prey back to their villages.