Game of Thrones deserves a mention. Minor character goes on patrol north of the wall. Gets pwned. Introduces us to the central conflict of the series in a mysterious way and sets the grim tone.

https://www.royalroad.com/fiction/26294/he-who-fights-with-monsters/chapter/386590/chapter-1-strange-business

He who fights with monsters. First few chapters are free. You will get addicted, I am.

The man in black fled across the desert, and the gunslinger followed.

Szeth son son Vallano wore white on the day he was to kill a king.

The first that comes to my mind is the prologue of The Name of the Wind by Patrick Rothfuss. It's beautiful prose with this hint of sadness and at the same time epicness and mystery. It made me want so find out more about the main character and read more of this poetic language.

I also love the opening lines of Wyrd Sisters by Terry Pratchett: "The wind howled. Lightning stabbed the earth erratically, like an inefficient assassin." Describing the weather is a really common opening, but Pratchett manages to put his own humorous twist to it. It unites setting the "stormy, witchy night" mood with setting the stage for his humour. The comparison is so absurd and so pratchetty, it never fails to make me grin.

The Name of the Wind is sublime. I think because it sounds so different to the usual grand, bombastic, bellicose fantasy kick off. It’s all silence. And a man working in a bar. And that last sentence. Oof.

It was night again. The Waystone Inn lay in silence, and it was a silence of three parts. The most obvious part was a hollow, echoing quiet, made by things that were lacking. If there had been a wind it would have sighed through the trees, set the inn’s sign creaking on its hooks, and brushed the silence down the road like trailing autumn leaves… The Waystone was his, just as the third silence was his. This was appropriate, as it was the greatest silence of the three, wrapping the others inside itself. It was deep and wide as autumn’s ending. It was heavy as a great river-smooth stone. It was the patient, cut-flower sound of a man who is waiting to die.

Full text here: https://www.goodreads.com/quotes/9410716-it-was-night-again-the-waystone-inn-lay-in-silence