Um Lannister sempre paga suas dívidas.
Para tudo o resto, MasterCard.
Existem coisas que o dinheiro não compra. Para todas as outras coisa existe MasterCard.
O inverno está chegando...
O norte se lembra.
Came here just to see this
Beware the White Walkers!
Why is the article not optional in this case?
Usually you use the article. You can speak without it and people will understand you, but I'm not sure if it's grammatically right.
I've discovered that it is customary and somewhat necessary to include the article in Portuguese on many occasions, including seasons.
Could you say "O inverno está vindo?"
Yes, but it is closer to English and sounds odd in Portuguese.