Oh also since it came up in the show: Kendra is immortal because she’s a witch. I can’t remember if she is 17 years old and just stays the same age, or if she’s like 300 and she uses her powers to make herself look young (because she can disguise herself to look differently.)
In one of the spin-off books to Beastly (there’s like 4 of them) we find out that Kendra is from the 1660s and a plague wiped out her whole village when she was 17. She had spent a lot of time learning alchemy from the village crazy lady who wouldn’t you know ended being a witch. Somehow the witchcraft ended up protecting Kendra from the plague but her whole family died in front of her. She was kind of bitter about it, but she also knew something was up and figured she should practice her new witch powers.
For the next 300 years she would try to help others that SHE thought would need help, such as our boy Kyle here, and sometimes it turned out okay but other times people ended up dying, or she would accidentally cause a witch hunt. She’s gotten in trouble a few times and other older witches would scold her, so she often tries to lay low. She’s chilling at the high school because that’s where a teenager would be.
So Kendra is a well-meaning witch, but I think because she’s technically a teenager, she doesn’t have all the foresight when it comes to “helping” people.