My comfort characters can shift over time or accumulate, usually when my special interests move on to the next media. Characters mostly become my comfort characters wgen they're relatable and/or fascinate me. Amanda is incredibly relatable to me, and I'm obsessed with SAW currently. In my opinion, Amanda is the main character of the original trilogy (which is my favorite part of the franchise), and every movie without her sucks at least a little bit. She's the most important character to the way John's values are challenged, because she has an arc.
Another character I obsess over is Jack Torrance from "The Shining". I'm currently reading the book. I love Stephen King, and Jack is very interesting and relatable (I'm not even an alcoholic, but he reminds me of my cravings for SH and I can learn from his problems. It has kind of helped me find a way to deal with these cravings).
I mostly find comfort in relating to characters and obsessing over topics.