Chiefs. (Come back to the Chiefs Notorious B.E.N. There's never been a better time. Unless you want to be accused of band-wagoning.)
I didnt really watch NFL until Peyton was drafted. Then I pulled for the Colts. But when they started treating him wrong, I became a free agent. He ended up in Denver and I pulled for Manning-in-Denver, but never really Denver.
(I was in a wedding in 2007-ish that was Denver Broncos themed. The colors were navy and orange. The bride was a huge fan.)
At the same time I was following Berry in KC. He got the cancer and all then was come-back player of the year. That was pretty much what made me a fan. The story though isnt directly linear. There was some overlap with pulling for Manning-in-Denver and KC at the same time. Sue me.
Then when Manning retired I made a clean break. It was all KC. They had Berry along with some other VFLs - lineman Zach Fulton, QB Tyler Bray. And of course Dustin Colquitt who, Sunday, set a record for most games played as a Chief.
Then the Chiefs traded up to draft Mahomes. I'll admit I thought it was a mistake. I thought Smith was serviceable and we should work on our defense. I was wrong. Mahomes. Wow.