Someone who supports a team (especially a football
team) that is neither based in or near the town of their birth nor is even anywhere near where the 'supporter' resides. Although family connection is often cited as a reason for said support, essentially glory supporters' only reason for supporting a team is them having a history, and future chance, of winning trophies. Typically, a glory supporter knows little about football and has rarely, if ever, been to watch 'their' team play.
99% of Manchester United fans are glory supporters, coming, as they do, from outside of Manchester.
"My Grandad was a Liverpool fan, so I have to be". Notice how such a glory supporter will automatically follow the most prestigious team that any other family member supports.