Word "fuck" was used in Legend of Vox Machina, because Critical Role players use it a lot in game. Simple as that. This show is redux of gaming session, not new Shakespeare or new Tolkien.
Is "fuck" an old word? Yes. No tell me where it shows up in Canterbury Tales or Beowolf. For estra credit, you can tell which of Shakespeare's works the word appears in.
Yeah, because obviously one can accept from high culture - like plays that can be watched by Queen, or works of Geoffrey Chaucer to use coarse language of contemporary soldiers, peasants and fisherfolk. That makes sense.
From Wiki: "Otherwise, the usually accepted first known occurrence of the word is found in code in a poem in a mixture of Latin and English composed in the 15th century. The poem, which satirizes the Carmelite friars of Cambridge, England, takes its title, "Flen flyys", from the first words of its opening line, Flen, flyys, and freris ('Fleas, flies, and friars'). The line that contains fuck reads Non sunt in coeli, quia gxddbov xxkxzt pg ifmk. Deciphering the phrase gxddbou xxkxzt pg ifmk, here by replacing each letter by the previous letter in alphabetical order, as the English alphabet was then, yields the macaronic non sunt in coeli, quia fuccant vvivys of heli, which translated means, 'They are not in heaven, because they fuck the women of Ely'. The phrase was probably encoded because it accused monks of breaking their vows of celibacy;[13] it is uncertain to what extent the word fuck was considered acceptable at the time. The stem of fuccant is an English word used as Latin.[24] In the Middle English of this poem, the term wife was still used generically for 'woman'.[‡ 1]
William Dunbar's 1503 poem "Brash of Wowing" includes the lines: "Yit be his feiris he wald haue fukkit: / Ye brek my hairt, my bony ane" (ll. 13–14).[25]
The oldest occurrence of the word in adjectival form (which implies use of the verb) in English comes from the margins of a 1528 manuscript copy of Cicero's De Officiis. A monk had scrawled in the margin notes, "fuckin Abbot". Whether the monk meant the word literally, to accuse this abbott of "questionable monastic morals", or whether he used it "as an intensifier, to convey his extreme dismay" is unclear.[26]"
That's about written word. But probable Nordic origin puts it's few centuries earlier. I'm sorry that Chanson de Roland is not a good source about how French peasants swore in XI century
Yeah, the term *Fuck* is actually pretty old, derived from old Germanic and Norse slang. The idea of using vulgar words being modern is simply a reflection o American whitebread prudishness. Dark Ages people used vulgar and coarse language all the time.
Indeed. Judging overall language from written language in countries and times where only elites often clergy could read and write is not a good methodology.