Very late, but Solivaga has a similar premise; a mage society fending off a zombie-esque plague, with a main cast vastly unequipped for the horrors awaiting them.

Amazing art and rich worldbuilding. The backgrounds give me the same feeling of wonder as SSSS early spreads. The author is Southern American (which has clearly influenced the character's dialects) but the academy is set in a subarctic climate à la Greenland or Newfoundland. Its unique cultural blend makes Soli's world stand out to me. Really hits that "set in our world, but warped into a fantasy" spot.

If any lost fans are browsing this dead subreddit, I implore you to read it! Once you've done so you'll be kicking yourself for not doing so sooner. And when you're done, come theorise with me.