Uncle Sean

Aka George Redmond because of how much he wanted to be anything but Irish. Actually, no 'cause he hates Irish Americans who claim they're Irish because, well, obviously, if they were indeed Irish they wouldn't have left Ireland in the first place! Duh!
Indeed, he's so proud of his Irish Heritage you need to understand Gaelic to be able to catch up his demands, otherwise don't bother talking to him because he refuses contact with anyone who isn't Irish.

He's a proud catholic (sometimes protestant) which makes us all quesiton why he and Aunt Margaret got divorced in the first place.

He loves to claim to everyone that unlike this devious generation that he actually is a multitalented person, he usually does so by constantly bragging that he plays the fiddle or the accordion and we all pretend to believe he does to spare us from his insistent trash talks or from his poor attempts to play those annoying things.

He laughs too loud, drinks too much, smokes too much. In fact, the part about being catholic or protestant is a bit questionable since alcohol is his main religion.

Always grabbing his sons and nephews in an awkward spot as well tickling them and undressing in front of strangers during St. Paddy's because he loves St. Paddy's a lot and because Patrick is a Saint who showed The English who's the boss.

Fun fact: because Ireland is the world's country of Incest it's basic common sense that Domhnall Gleeson and Uncle Sean (George Redmon) are direct relatives.