- Father Gascoigne is the Wake-Up Call Boss to end all Wake-Up Call Bosses. Potentially the first or second (depending on whether you fight the Cleric Beast first) boss you encounter, he is entirely designed to teach players to adapt to Bloodborne's aggressive combat style and Nintendo Hard difficulty. He fights the player like an NPC or PVP player would - he dodges your attacks, he tries to parry you with his gun, and he never lets up. He also transforms his Hunter Axe into the two-hand version, giving his attacks serious reach. His third phase is where most players perish within a matter of seconds; he fully transforms into a beast, gaining extremely quick, aggressive attacks which often combo into each other, leaving you stunned on the ground while he quickly destroys your health bar. Unless you've spent most of the game so far practicing dodging and stunning, good luck. If you found it, the Tiny Music Box will stun him for a few seconds, which can be a blessing during his beast form (or human forms, if you need the help), but it has its drawbacks. It doesn't immediately stun him, leaving you a sitting duck for a critical moment, and it will only work a few times. Even worse, if you're unwise enough to overuse it before the transformation, he'll actually turn into a beast early, leaving you to fend off a Lightning Bruiser with extra HP and no music box to counter him.
- Vicar Amelia. Father Gascoigne was the first boss to show you how punishing the game can be, but Vicar Amelia is made to cause rage. She has a large health pool compared to previous bosses and her attacks cover wide and long areas, so keeping your distance without being sliced to pieces is difficult. In her second phase she will become much more aggressive and can even heal if you make the mistake of keeping your distance, forcing you to throw Numbing Mist at her to stop it. As an extra "screw you", her Rapunzel Hair tends to completely fill the screen when you're behind her, making it impossible to see what you're doing. Be ready with Fire Paper and a good Serrated weapon, especially if you're courageous/skilled enough to decide to take her on early.
- Rom, the Vacuous Spider requires a great deal of patience to beat. Unlike the game's other Flunky Bosses, her minions are a huge threat—one attack will reduce most players to one-third their HP—requiring you to split your attention between the boss and the minions. Even worse, with each stage she'll summon more. If you want to play it safe, you can try to thin out the spider swarm before engaging Rom herself, but doing so is very time-consuming and open you up to a quick death by Rom's meteor showers while your back is turned.
- The DLC, The Old Hunters brings the first boss, Ludwig the Accursed. A gigantic beast with over a dozen unique attacks, incredible speed and strength, with difficult to predict movesets and tells complete with savage combos. Ludwig is known as a skill check for the DLC, with several attacks fully capable of oneshotting a careless, or even careful player. Halfway through the fight brings the Holy Blade phase when the tempo changes and Ludwig wields the Holy Moonlight Greatsword. His strikes are frenetic and fast paced, with power AOE strikes and massive damage. Unsurprisingly, he's considered one of the greatest bosses in the game for his incredible, but fair, difficulty.
- The Optional Boss of the D Lc, Laurence the First Vicar, is a reskin of the Cleric Beast with a fire theme. The bane of many players, Laurence completely ditches the 'tough but fair' challenge in favor of attacks that are just a touch too aggressive and savage, with difficult tells, sweeping range and insane damage that requires a total lack of room for error. His final phase brings with it insane combos, leaving a trail of damaging lava and incredibly few windows for attack. Small surprise he's considered one of the most nightmarish bosses in the game.
- The penultimate boss of the D Lc, Lady Maria is the Astral Clocktower is known for her difficulty. With swift and graceful strikes, Maria combines the pure skill of a veteran hunter and is capable of dodging most anything you dish out. While her first phrase can be strafed about, her second and third phases bring the pain whe using her Blood Blades enhances her reach and damage enormously, coupled with increasing aggression. Like Ludwig, she's also considered a high quality and difficult boss, but one of the game's highest challenge.
- The final boss of the DLC, the Orphan of Kos is considered one of, if not the hardest bosses in all of FromSoft's history. He is almost mindlessly aggressive and hard-hitting and while his first phase is comparatively simple to master, his second is the player killer. His attacks are nigh-impossible to parry, with painful and relentlessly combos, chaining AOE attacks and powerful lightning blasts that are exceptionally difficult to dodge if you stand in the wrong place. Finding windows to attack is hard enough, compounded by his insane health poor. Not for nothing is he known for his psychotic levels of difficulty to cap off the very difficult Fishing Hamlet.
- The Bloody Crow of Cainhurst. He only appears in the Grand Cathedral if you complete Eileen's quest line, after you find her wounded outside the door. He could potentially be the hardest hunter NPC fight in the entire game, he has a gigantic health pool standing at exactly 3510 which is the equivalent if not more than some of the bosses you face. Not to mention he also has maxed out stats and deals extreme amounts of damage, his Repeater Pistol can take half your health and he likes to use this constantly after dodging one of your attacks. Oh, and he likes to regularly use Old Hunter's bone which turns his strafing/dodging into outright Teleport Spam. You know a fight is especially difficult and brutal even by Soulsborne standards when the most common "recommended" strategy to beat it is by using a Good Bad Bug to exploit the Hunter AI with Blue Elixirs...
- If you're exploring the Chalice Dungeons and following the natural progression of dungeons you unlock in the course of unlocking the dungeon to the Pthumerian Queen, you are very likely to find yourself fighting the Watchdog of the Old Lords, which is a dog the way Cerberus is a chihuahua. While this beast is not much different from the giant monsters most players have been slaughtering by this point, what makes it an infuriating boss fight is the dungeon type in which it's fought in: a (Cursed and) Defiled Chalice Dungeon, which reduces your HP by half. This means that even at high Vitality, the Watchdog can and will oneshot you with several of its attacks, and because it's so massive, it can obliterate you just by clipping you.
That One Boss / Bloodborne