YA Christian Supernatural series about siblings who fought Demons. Read around 2004-2005.

[Kali]

I've been trying to find this series for YEARS. I read them around 2004/5 . It's a long (15ish books) series about a brother and sister who have to exorcise demons and save people. It's not Peretti, but they came out around when the Hangman’s Curse became popular. I feel like it has the word “key” in its series name but I’m not entirely sure. I vividly remember the sister being described as mousy with “hair colored hair.”

I hope there are some other unfortunate souls that were only allowed to read Christian books like me and can help me remember!

[Library]

Is it this series?

https://www.goodreads.com/series/5983...

[[deleted user]]

Fablehaven
https://www.goodreads.com/book/show/4...

[Rainbowheart]

The Society for the first book in the Forbidden Doors series.

If not, does anything on the Christian Series for YA and Middle Grade list look familiar?