I guess they started with something to offer... we now have cloud feudal "lords", who started by offering services, and then make you follow their altering terms and conditions, who they can change and all you can do is pray that they don't alter it any further. Just like real feudals, the cloud feudals can one day decide you did something wrong, and there's no trial, just direct banishment.

Even worse if your income depend on these feudals (e.g. all the gig-workers who are working without the benefits that exists with an employer-employee relationship).

But to answer your question, I guess it would've started with cooperation between friends/neighbors, the "alpha" person would've led the group of people in some sort of enterprise, his son became the next leader because that's how that was done, this enterprise got bigger and stronger that it encompassed land and resources, and people would want to work for them to earn a living. Heh some even owned navies and colonized places half around the world (the various East India Companies), some are content to work locally (various Mafias).

Games and articles and anime all include "lords", as far as I can tell. But feudalism wasn't universal, there were lot of (what we today would call) countries without feudalism. There could still be (fairly local) kings, but farmers owned their lands and nobility didn't necessarily exist at all, in some places. But games (including anime) tend to focus 100% on the feudal system.

There is a strong incentive to displace the existing one, but if you're strong enough to do so, wouldn't you rather become the belligerent parasite rather than eliminate the idea of belligerent parasites? And so the cycle begins anew [0].

[0] https://en.wikipedia.org/wiki/Barracks_emperor

The same way "wealth creators" do today?

https://en.wikipedia.org/wiki/The_Dawn_of_Everything muses about that

Well when they have swords, horses, and armor, and you don't, your options are limited.