Specific details aside, let's move on to the /immortal/ side of the world, Katherine (Kato).

One of Kat's parents is an immortal, the other is mortal. Her younger brother (by a few years), Shaun (yes, the same Shaun that is Sally's love interest as discussed previously) is mortal. Kat was born mortal, but was granted the power of being one of the seven guardians of the seasons, which ensure that the seasons, each controlled/ruled by a magical witch/wizard, transfer over smoothly each year.

Seasons transition:

The witches/wizards of Spring, Summer, Fall, and Winter rotate a magical staff that will allow them to rule over the mortal world for a fixed amount of time. But as greedy immortals, they, of course, don't want to give up the power once it has been handed. (Sometimes, Spring comes later than winter! Why does it snow in April in some places of the [northern hemisphere] world?)Thus, they often try to wreak havoc on the mortal plane or battle each other (sometimes via their Apprentices). The seven animal guardians were established in order (more talking animals). They take name after gods/goddesses from ancient civilizations (hey you guessed it -- the cat is Bastet, as per the Painting). These animals train young mortals/immortals to keep peace between seasons.

The seasons each have two apprentices, one male and one female. One of these two will take the seasons place when they die (or retire to a beach or ice cave or whatever they want).
Spring: Lily, Louis
Summer: Carol, Chris
Fall: Melissa (dark wavy dark hair, kind of lazy), Morin (dark hair)
Winter: Jade (cape, carries broom), Jake (Jade's twin)

This story follows Kat, the current (surprise lol) Feline animal guardian. Basically she can turn into different types of feline and fight the seasons or whatever. She has short blonde hair which is dyed purple at the ends (wow edgy!). She's a very ~cool~ teenage girl. Her two best friends are Annie, some girl from school, and Cody, her next door neighbour (we'll discuss them more later). Cody has the whole like, we-can-open-the-window-to-say-hi-to-each-other-like-in-a-Disney-movie-neighbour vibe going. Neither of them know about her Catness.
Her magical talking animal, Bastet, masquerades as her pet black cat, and only tells her to go training and whatever when she needs to.
Her closest friends that are animal guardians are Sophie (brown hair, ponytail, likes blue hoodies), the Avian guardian, and Tristan (tall, dark, mysterious, dark hair, doesn't like to smile), the Canine guardian. Tristan is also her love interest, which is funny because cat and dog.
The other guardians are Andrew (Ursa, and also younger brother of her bff Annie), Ray (??), Hailey (fish), and ?? (??).