The kanima is the result of a mutation of a werecreature's transformation. In the Teen Wolf universe, an idiom comes into play: "Sometimes the shape you take reflects the person you are." A werecreature will transform into a kanima due to a rooted insecurity that they lack a sense of self-worth, an personal identity. As a result, the kanima doesn't know what or who it is. In 2x04 - Abomination, it is shown to be confused and scared of its own reflection. To this end, they purposefully seek out a Master to serve as their slave, and to form a bond with a potential Master.
A kanima cannot become the werecreature it's originally meant to be until it resolves this state of mind, discovering its identity. It then has to be killed. Subsequently, the shapeshifter will be reborn as it's proper species.
Main article: Shapeshifting
The kanima is reptilian in appearance. In the Teen Wolf show, the kanima can transform into two known shapes. In a partial-shift, the creature will initially appear as its human guise with a gradual number of shifted patterned scales.
The kanima can transform into a bigger shape after undergoing an evolution. The venom that secretes out of its claws will form a coccoon which incases the shapeshifter.
Eventually, the kanima will emerge a much more powerful creature. Its front clawed limbs will become wings, a row of ridged spikes sprouts from its head, and its tailtip is now a spiked club.
As a shapehifter, the kanima is capable of enhanced strength and speed that add to its formidability.
In Ice Pick, a kanima, Jackson Whittemore, in his human guise, was able to exert enough strength that he easily lifted his car three feet into the air. In Abomination, the kanima could move around in the school's swimming pool, then leap, and scale up the side of the wall, and jump out the window of the roof with massive speed and reflexes.
In Venomous, Jackson discovers he has enhanced hearing, being able to hear Danny Mahealani turn on a water tap in a bathroom, whilst in a boy's locker room. Likewise, Jackson's able to hear Scott McCall, Stiles and Allison talking fifty yards away from the inside of a van.
Main article: Healing Factor
A Kanima also has a tremendous healing ability.
Jackson Whittemore survived an entire round of gunfire from Chris Argent and simply reverted back to human form after Derek tore out the kanima's throat with his teeth in Frenemy, it simply pulled out an arrow to its head and still kept on fighting from being stabbed in the chest and its side with daggers in Fury.