The best of the three mains acts, and also those in the DLCs.
The Royal Griffin
A fearsome fight at the beginning of the game, the Royal Griffin lunges at you with its beak and talons and screeches at you loudly as it does so.
The first opponent you fight from The Wild Hunt. Nithral‘s got quite a scary, gravelly voice and a big axe that can kill in just a few hits.
Ladies of the Wood (fighting as Ciri)
Arguably the toughest boss fight in the whole game. Ciri is fast and deadly, but these three witches are more then capable of killing her instantly. They constantly press and each have large health bars, so take time to wear down. Whereas Ciri will be struggling for health under normal circumstances and running around in circles trying not to get hit. Make no mistake: the Ladies of the Wood are a tough boss battle, and being so challenging makes them even more memorable.
Imlerith (fighting as Geralt)
A second, difficult boss battle, straight after the Ladies of the Wood fight. I like that kind of challenge! Imlerith has three different attack stages and can kill you with one swipe of his very big mace. Beating him on Death March difficulty is especially challenging.
Caranthir (fighting as both Ciri then Geralt)
Starting as Ciri then changing to Geralt. Not an easy fight. Caranthir summons ice elementals to attack you, and can blast you with a devastating frost wave. A more difficult fight as Geralt, than as Ciri.
Eredin (fighting as Geralt)
The final boss battle of the main game. Eredin is a tough cookie – especially on Death March difficulty. He uses portals to move to different stages and has a variety of different attack waves. Figuring them out and beating Eredin is what you have to do to stop The Wild Hunt.
Hearts of Stone
Olgierd von Everec
A humorous fight, with Olgierd von Everec, at the beginning of Hearts of Stone. He’s a tough opponent, but if you beat him you will be rewarded with one of the most shocking and funny gaming moments of all-time.
A freaky-looking, faceless creature who tends the gardens at the von Everec Estate. He carries a big, rusty shovel and will attack you the moment he sees you.
The Wraith From The Painting
Quite a tough Wraith who attacks Geralt from a painting in the von Everec house. She keeps regenerating her health by returning to the painting. To beat her you have to stop her doing that.
Iris’ Greatest Fear
For my money: the most disturbing opponents in the game. They are supposed to look (and fight) like charred, distorted versions of Olgierd von Everec, which makes them look very strange (and fight very hard). You fight six of them during the finale of Hearts of Stone, and to say they’re not easy is an understatement. There’s a fun achievement available for those brave enough to beat all six at once, rather than fighting them one at a time, which is the standard way.
Blood and Wine
I shouldn’t really add these because they’re not technically “bosses” (because they’re not required to win the game), although I have added them because they are arguably the most difficult opponents in the entire game. They are very overpowered statues that come to life during the “Extreme Cosplay” quest and they have huge health bars and deadly hits. In fact: there are four of them, and winning this fight will involve you backing off to areas they can’t get to, to heal up. If you weren’t able to hide from them, you’d be toast. Getting a few blows on to these guys is hard enough. They’ll kill you in two or three hits.
The Wicked Witch
The Wicked Witch looks so amazing that it’s almost a pity to kill her, which is required, but only if you’re doing the Blood and Wine Syanna branch of the quest “Beyond Hill and Dale“.
The Big Bad Wolf
The Big Bad Wolf has a hilarious French accent. A reasonably challenging and entertaining boss fight.
Not quite as interesting as some of the other “Land of A Thousand Fables” boss fights. Longlocks is basically a unique type of Wraith.
The Cloud Giant
Now The Cloud Giant is more imaginative! Reminding me of something from the imagination and camera of Ray Harryhausen. It’s a fairly easy boss fight though.
The Hermit who guards the sword Aerondight, in the quest “There Can Be Only One“. You have to fight him while standing on water. He’s tough too and can easily whack you before you even trouble him. To beat him you’ve got to focus and bring your A game.
Only available during the quest Blood Simple in Blood and Wine. The Alpha Garkain looks more fearsome than it actually is.
Dettlaff van der Eretein
The final boss battle in Blood and Wine has three distinct stages and they’re all fairly challenging. The final third stage is relentless and the only way to survive it is to keep rolling and try to get hits in whenever possible.