Caitlin 'Tee' Isis Wolfe is an Azure Blood who was changed by Skye Alcotte in 2013. She is the fastest Azure, however she is also the youngest, both in terms of her human age and the amount of time she's been an Azure Blood.
The first Azure Blood Tee properly met was Skye, in 2007. They have bonded since then and are now very close friends and consider themselves sisters, partly because they're so close but partly because Skye's boyfriend - Ace Fillmore - is Tee's older brother.
Tee is also very close to Pablo Chastel, as they were in the same class at their old school. It is a massive surprise to Tee when she finds out that Pablo is now an Azure.
Tee and Luka are best friends. They've known eachother since the early 1900s, when Tee gave Luka the potion of eternal life. (see Eternal Life).