If Monster Hunter: World is your first Monster Hunter game, you may have occasionally seen this question floating around: what was your first Monster Hunter game and what weapon did you start with? It's interesting. While I haven't seen this bit of trivia confirmed, it's widely believed that the fifth fleet you're apart of in World represents the fifth generation of the Monster Hunter series, and each fleet before it represents the previous generations of the game.
For example, the first fleet hunters in the game like the Commander and the Huntsman are tired, grizzled veterans who have done it all, like the players who started playing the games way back when. The third fleet is composed of researchers and scholars, just like how Monster Hunter Tri brought lots of online resources like the wiki and Kiranico.
via destructoid https://www.destructoid.com/is-world-your-first-monster-hunter-game--492240.phtml