A shapeshifter will transform into a kanima due to the deep-rooted feeling that they lack a personal identity, lack self-value. As a result, the kanima doesn't know what or who it is. It is confused by its own reflection to this end. To this end, they purposefully seek out a Master to become enslaved by, and form a bond with him/her.
Jackson's mental issues and outward behavior, his innate desire to feel accepted by people, to make others proud of him, his borderline-aggressively competitive nature, and his feelings towards his adoption and being an orphan, resulted in him exhibiting such a mindset. And so, when he was bitten by an Alpha, instead of a Beta werewolf, the kanima shape manifested.
Also, unlike other shapeshifters, the human side of the shapeshifter is displayed as being completely separate from the kanima side. Jackson wasn't immune from the creature's own venom.
Stiles Stilinski: "When's the Kanima not the Kanima?"
Scott McCall: "When it's Jackson."
Main article: Shapeshifting
The kanima is reptilian in appearance. In a partial-shift, the creature will initially appear as its human guise with a gradual number of shifted patterned scales.
Its primary features include claws, greenish-yellow slitted eyes, and multiple rows of greenish chrome teeth. A Kanima's claws secrete a neurotoxin that renders their victims paralyzed. Often, this is administered via a slash to the back of the neck, so the toxic will go to the spine.
When a kanima is fully transformed, it becomes completely bald, it's skin morphs into a dark-green hide, it can scale walls similar to a lizard, and grows a powerful prehensile tail.
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.