I'm so glad to finally be posting this entry. I first made it over a year ago but I've been holding onto it because I don't like posting before the character has actually debuted, even when I know when and where they'll debut. And then I missed the debut by several months, so this should have been posted back in October.
A couple years ago, Disney Korea began publishing a manhwa-style webtoon called Avengers: Electric Rain, which is set in Korea and features a familiar (read: movie) lineup of Avengers, with one new addition: White Fox.
White Fox appeared in the first entry (September 2014) and is a Korean superhero based on - or may actually be - the kumiho, or Korean nine-tailed fox spirit (similar to Japan's kitsune).
White Fox was first seen in American comics on the cover of the video-game-tie-in-yet-still-in-continuity Contest of Champions #1 (October 2015).
She has since appeared in every issue of the series, save one (but she appeared on the cover of that one). She has also made an appearance in Deadpool #1 (November 2015).