While Resident Evil isn't a franchise synonymous with its boss fights, like Yakuza or Metal Gear Solid, they're still a key aspect. Resident Evil has many iconic monster designs throughout its nearly 30-year run. However, it's also important to note that the monsters themselves are often as deadly as they look. Some of the boss fights throughout the series can be brutally hard and frustrating, leading to you never wanting to see them again after they're defeated.

Certain Resident Evil games are the hardest to 100% complete already, and these fights complicate matters exponentially. These fights are hard for various reasons. It can be difficulty mode-related - a specific version is a problem, troublesome controls, low resources, one-hit kill deaths, and even it just takes too long. Keep in mind that there will be no mini-bosses like Dr. Salvador or the Executioner.

10 Infected Bat: Resident Evil 0

A Boss With Allies More Powerful Than You Think

The third boss in Resident Evil 0 is the Infected Bat. You're given a nice save room right before the boss encounter, and you'll need it because this may take a few tries. The problem with the Infected Bat is his small bat allies that surround him. These small bats do nothing, but the auto-aim ruins everything. The auto-aim will often lock onto these small bats and not the actual boss you're trying to kill.

This is really annoying, and the Infected Bat will often take advantage by doing attacks when you're trying to aim. The boss arena is huge, too, which makes it even harder to shoot him. I'll it that it took me a few tries to beat the Infected Bat on my first playthrough, and I'm pretty good at classic Resident Evil.

9 Queen Leech Second Form: Resident Evil 0

You'll (Hopefully) Have Just Enough To Get By

Hard difficulty in Resident Evil 0 is a significant step up from Normal mode. A ton of ammo pickups disappear on Hard, and this makes the final boss, the Queen Leech, incredibly difficult. In horror games, it's best to save up most of your ammo for the endgame bosses, and this proves to be especially accurate here. The first phase of the Queen Leech Second Form works like a traditional Resident Evil boss. You shoot it until it's dead.

I think a person less skilled in my position would struggle for hours to beat the final boss on Hard.

The second phase is where it gets hard. At this point, you're probably drained of all your heavy-duty ammo and must resort to using the pistol to direct the Queen Leech away from your partner. This is quite tricky, with both your ammo and healing item resources dropping fast, and you must manage them carefully.

8 Yawn: Resident Evil 1 Classic

Auto-Aim Is The Big Dealbreaker Here

Yawn, in the original 1996 Resident Evil, has to be the most fascinating hard boss. In most versions of Resident Evil 1 Classic, Yawn's second fight is around a standard difficulty level. It's just challenging enough for a boss around two-thirds into the game. However, the original 1996 PS1 release (not the Director's Cut version) makes this fight one of the hardest in the series.

This is because the original version didn't have auto-aim. For a boss slithering around the floor, using manual aim for every shot is a nightmare. Yawn, by itself, requires a balance of shooting and evading its attacks, and with only manual aim, getting shots in can be a Herculean task. Make sure to save up your healing items for this fight if you ever play the launch 1996 RE1.

7 Lisa Trevor: Resident Evil 1 Remake

Scary One-Hit Deaths Make This A Real Challenge

There's a reason why many consider the 2002 Resident Evil the best remake of the series. It added so many things to the RE1 package, including a new boss: Lisa Trevor. She's one of the scariest monsters in the franchise, and her final fight before entering the Laboratory is also scary, but for a different reason. To be frank, this boss encounter is easy for the most part, but the one-hit kill deaths will always be in the back of your mind. To win this fight, you simply need to push over the four stones around the arena.

Lisa will often chase you here, and if she hits you while you're close to the edge, you'll fall off, and it's instant game over. Of all the times I've died in Resident Evil 1 Remake, the two most common deaths occur from the boulder and the Lisa Trevor one-hit kill. Again, this boss fight can be easy, most of the time, but the nasty, worrying one-hit kill deaths have to make this fight at least on the lower end of the hardest bosses in the series.

6 Nemesis Second Form: Resident Evil 3 Classic

A Savage Brawl That Can Take Down The Best Players

Even in a game that's one of the easiest Resident Evil titles to 100% complete, RE3 Classic has one of the hardest endgame bosses in the series. It's not the final boss of Nemesis, but the one right before in the Treatment Room. Here, you'll face the second form of Nemesis, and it's no joke. The monster's attacks are brutal, like slamming you onto the ground with its tentacles, and it deals a ton of damage.

When even the best players die in a boss fight, you know how truly difficult it is.

Nemesis is no glass cannon either, as it'll take dozens of grenade launcher rounds to defeat it. However, this can be helped by the valves. If interacted with, these valves will spray liquid that'll harm Nemesis, but it's very situational. The arena you fight in is very tight, and it can be easy to back yourself into a corner, making Nemesis even more deadly.

At Awesome Games Done Quick 2018, during the speedrun race between Bawkbasoup and Wusscake, Wusscake actually died here. When even the best players die in a boss fight, you know how truly difficult it is.

5 Nosferatu: Resident Evil - Code: Veronica

The Second Most Frustrating Boss In The Series

Resident Evil - Code: Veronica has a couple of savage boss encounters, but the one that sticks out the most has to be Nosferatu. Appearing at the end of Claire's section before moving on to Chris, almost everyone will die at least once to this boss on their first playthrough. The problems of this boss are immense. Firstly, the arena is quite tiny. This makes avoiding his attacks significantly harder, and the attacks in question are brutal.

Nosferatu can spray out purple gas, and they're an absolute pain to avoid in such a tight area. He can do his poke attack with his huge arm, and that can make you fall off the edge and die instantly. Plus, his only vulnerable area is right in the heart. To be frank, I would recommend first-timers to simply practice with the Sniper Rifle and kill Nosferatu with four heart shots. You're given seven Sniper shots total, so just try repeatedly until you nail four. It's much easier than any other route, but it still requires some practice.

4 Morpheus Second Form: Resident Evil Dead Aim

The Most Frustrating Boss In The Series

I hardly ever rage quit video games, but that's exactly what I did with Resident Evil: Dead Aim. For those unfamiliar with Dead Aim, this Resident Evil title was the last in the Gun Survivor series, which were light gun-focused games. Despite these entries being built from the ground up with light guns in mind, you can still play them with a controller, and this is where the problem comes in.

I just barely managed to keep the boss away from me to reach that point, and when the rush activated, it was instant death.

The final boss of Dead Aim, Morpheus, has a weak spot that moves around as it slowly approaches you, and trying to hit this thing with an analog stick is extremely frustrating. It also doesn't help that Morpheus approaches you faster the more it's hurt. I actually managed to reach the final move, where it rushes straight at you.

I just barely managed to keep the boss away from me to reach that point, and when the rush activated, it was instant death. That's so cheap, and every time you die, you must redo the entire final section of the game again. Don't even bother playing Dead Aim without a tube TV and an actual light gun because it won't end well with a controller.

3 Ramon Salazar: Resident Evil 4 Remake

A Complete 180 From The Original Game's

When looking at Ramon Salazar in the original Resident Evil 4, he was actually pretty easy. You could buy a cheap Rocket Launcher and kill him in one hit, but Resident Evil 4 Remake fixed that. Ramon Salazar is now the hardest boss in the entire game. Rocket Launchers are significantly more expensive in the remake, so that old strategy won't be viable for most people.

Salazar's new attacks are on a whole other level than the original. They're incredibly difficult to evade and will require a lot of practice. Plus, Salazar, on his own, moves around so much that it's often difficult to even get a shot on him. On my first playthrough, it took hours to beat Salazar, and I got really sick of his opening dialogue every time you started the fight. That level of practice to beat him is rare for an RE boss.

2 Uroboros Mkono: Resident Evil 5

A Boss That'll Refuse To Burn Down

Back when Resident Evil 5 first came out, Uroboros Mkono had to be the hardest boss I've faced yet in the series. I had a hell of a time trying to beat it, and the main problem was that it took a ridiculously long while to drain all his health. For this fight, you're supposed to use the Flamethrower to burn Mkono down, but it takes so long, and his attacks are deadly when they land.

I had to go back to Chapter 3-1, grab the Rocket Launcher, and do the whole level over again just to kill this boss in one hit. Still, to this day, I've never defeated this boss in the way Capcom intended due to how long it is to burn Mkono to the ground. It's just too hard, and not in a good way like Salazar from RE4 Remake, which proves to be a good challenge.

1 Mia: Resident Evil 7 Biohazard

The Hardest Part Of The Hardest Difficulty Is Actually The Beginning

Resident Evil 7: Biohazard was a true return to form, not only in of its general gameplay but also its difficulty. Madhouse mode was pure Resident Evil, managing resources to the fullest, as well as remixing enemy locations. However, it's strange that the hardest part of Madhouse happened to be the very start. Mia with Madhouse stipulations is a deadly combination.

She can kill you extremely fast, movement is limited, and you'll need every last bullet. Make sure to go for headshots, and you can't afford to miss too much. Another handy tip is to utilize blocking, as that will negate many of her attacks. It'll still take many attempts to beat this encounter, and, unfortunately, the rest of the game on Madhouse isn't much easier, making it the most difficult boss in the Resident Evil series.