Sounds quite like EVE (at least in its unconsensual PvP aspect), isn't it?
This is my favorite pastime in a Soulsborne. I tend to play a villain, and carry a fast, hard-hitting close-range weapon so that I can punish overconfidence with ruthless efficiency. Over time, I've gotten good enough that instead of dreading running into a full squad, I relish the opportunity to draw them out of position and murder them one by one.
Non-consensual PvP in Soulsborne is very much a "thing," but works rather differently from Eve. It's not an MMO. If you invade a player's world, that's exactly what you're doing: leaving your own game and spawning into theirs for the express purpose of finding and murdering them. The specifics vary based on exactly which game you're playing, but usually the prerequisite for invasion is also the prerequisite for summoning help, and mostly the "help" can't AWOX and gets no benefit from doing so other than the joy of standing by like an ass while the summoner gets killed. Frequently, therefore, invading another player's world means facing that player plus a couple of co-op partners.
PvP etiquette is actually something of a "thing" in Soulsborne. Players squaring off one on one normally bow to one another before dueling, and after, and a fair duel based on pure combat skill is the expectation. If the opposition has friends or plays dirty (for example, by attacking while you're bowing or having a coop player hide and ambush you mid-"duel"), however, anything goes.
An invader is almost always considered a "monster" by the level, and will both be ignored by and unable to take damage from creatures in the level (traps and environmental hazards are another matter). It doesn't matter for the invader's purposes how a world master dies, so there are all kinds of evil games an invader can play: turn semi-invisible; turn into an object native to the environment (such as a barrel in a room full of barrels); force-blast people off of narrow ledges; hide out near a major fight, and backstab the world master while the minions are busy fighting off the nasties; and on and on.
I usually use the environment to split up squads so that I can gank helpers or assassinate the world master while others are busy fending off the nasties. You can certainly use all the above tricks against even a single player (though if you take time to hide, you're also giving them time to summon help).
I started out mostly playing like an assassin, finding hiding spots from which to launch a single, absolutely devastating attack. Over time, though, I've gotten to increasingly be a dedicated duelist-- I normally don't go for no-holds-barred unless someone has friends or really pisses me off (again, attacking while someone is bowing is seriously bad manners, even if you fully and reasonably expect them to kill you as soon as they finish bowing).
Successfully snicker-snacking my way through two co-op players and the world master is the closest feeling to beating a Soulsborne boss for the first time I've found.
Specifics from specific games:
Demon's Souls - vanilla invasions, as described above, but there's a wager on. If you invade a world and lose, you also lose a character level. Winning means gaining about half the souls needed for your opponent's previous "level-up." Winning the match also means you recover your humanity (instead of basically being a ghost), which means you get extra health, can summon players to aid you, and can be invaded, yourself.
Dark Souls - two convenants can invade without restriction or cost, the Darkwraiths (<3) and Blades of the Darkmoon (Grr). The former appear as dark spirits who hunt for the rare resource known as "Humanity," and have access to a weapon whose special attack drains it (the attack's so hard to pull off that it's rarely used, tho). The latter are avengers; they only invade Darkwraiths and other malefactors, and collect their ears as trophies; these can be traded in for some of the nastiest cleric spells in the game. The Forest Hunters covenant also invades, but only in defense of a specific area.
Dark Souls 2 - soooooo many nifty changes gone to waste because they didn't want to have level 1 Pyromancers skill-shotting their way into the PvP covnenants and hunting noobs with high-end kit (this was an issue in DS1). To avoid it, they made character level irrelevant for matchmaking and focused on total souls acquired by a character EVER, including all the ones you lost because you got killed in a bad spot and couldn't retrieve them. Complete ASS. You can be invaded at any time in this one, by the way-- just only by people at around your own "Soul Memory." Nobody gets to invade "for free" anymore; everything costs, in one way or another.
Bloodborne - free invasions are back, but only players with a "bell ringing woman" in their level can be invaded (she appears if you summon help or attempt to invade, or pre-spawned in certain Nightmare areas which therefore attract the bulk of the game's PvP. This is the only Soulsborne game in which the ability to be invaded is, itself, killable). Has both my favorite PvP weapon (the Chikage, a blood-drinking poisonous iaito) and my favorite anti-ganker tool (Lead Elixir, which makes you impossible to stagger/stunlock and reduces damage, but keeps you from running). Combining the two of them lets you casually slice a full squad of coop players to ribbons if they all rush you at once and try to just beat you to a pulp.
Of special note, Bloodborne is also the only game that lets you AWOX-- though it's in a very specific manner. Two of the game's covenants are sworn enemies, so you'll be hostile to any player of the opposed covenant who summons you to "help." There's also a covenant dedicated to killing anyone
who has become a "blood-addled hunter," which seems to mean anyone who does much PvP or has murdered innocent NPCs; in either case, you end up spawning in the player's world not as a "blue" phantom (co-op) or "red" phantom (hostile), but a "purple" phantom, (would-be co-op turned hostile).
Every so often you run into someone who doesn't know what the purple glow means and assumes you're friendly....
One important caveat: Bloodborne's item upgrading's a bit simplified; all armor starts at its max stats. Weapons, however, do not, and the armor is balanced with max-statted, blood gem-modified weapons in mind. Early-game PvP therefore isn't really a thing, since even the nastiest (eventually) weapons might as well be made of nerf.
Dark Souls 3 - no idea. Can't wait to find out!
That whole series always seemed a bit too massochistic for my tastes? These sorts of opaque Japanese gameplay structures remind me of the early Resident Evil games; there was a lot to like, but mitigated by some unnecessarily punishing design choices.
Still I'm happy that a 'hard' game is seeing such success, considering how terribly easy and laughable most games are these days.
You ever want to cry for this generation watch one of those 'teenagers play NES games' youtube videos and watch as games you crushed as a small child stupify and terrorize modern teenagers. They literally can't get through mega man 1 or contra.
Eh-- I wasn't actually very good at those (though my family did lack an NES, so, want of practice, maybe?), and Soulsborne isn't actually nearly that hard. It's mostly about patience and observation (and, yes, a bit of masochism). A death you learn from in Soulsborne is a good death (though it may not feel like it at the time).
A major mistake From Software made with Dark Souls 2 was thinking that difficulty was the series's real selling point. They focused on it to a considerable fault; atmosphere, environment design, boss design, immersion, storytelling, and overall "feel" suffered badly. It's also the only one in which I hate the PvP, which is a little funny because PvP is supposed to be DS2's saving grace. (The Scholar of the First Sin revision supports enough players in one world-- seven, maximum, I believe-- to turn a level into a running skirmish).
Challenge, and the satisfaction that comes from bypassing a difficult obstacle, are a necessary ingredients. They are not the be all, end all.