Awesome Music: Captain O'Kane, the first game's title music, and The Clergy's Lamentation, the background music for the town of Grove: two hauntingly beautiful arrangements of Turlough O'Carolan's compositions that somehow makes the hours upon hours the players would spend fishing in town (rather than battling monsters in the dungeon) tolerable, or even enjoyable.
Demonic Spiders: The Widow Queen, its Widowlings and the Vile Tarantula. With a small group of Widowlings following it around, the Widow Queen will employ Zerg Rush if it sees you. The Vile Tarantula is not only relatively difficult to kill, but can also ensnare you with its Web Spell for a short time, effectively preventing you from fleeing and allowing other monsters nearby to beat you up. Consistent across all three is a scratch attack that often causes poison for nearly two minutes.
There are also the Spindly Creepers and Chittering Horrors. Like the two mentioned above, they can poison you, and their poison will drain your health extremely quickly. On top of that, they can web you too. Have fun.
There are also the elementals at early stages. Specifically, the magic elemental. The magic elemental is immune to all elements and magic. They can use Haste to make themselves outrun you along with being Sturdy and very damaging
The above are nothing compared to Diseased Centipedes and Armored Sharphorns
The Diseased Centipede, though rather fragile, can end you if it manages to poison you since said poison deals ridiculous amounts of damage.
The Armored Sharphorn deals very high damage and can easily tank your strongest attacks at higher levels. Their only weakness is their low speed
Lets just say every Elite and Legendary enemy that isn't a Zombie or a Basilisk can qualify on Legend.
Any crossbow wielding enemy, as they can easily chew through your health from afar even if you can't directly see them, making them a real pain regardless of how much of a distance you can maintain.
Good Bad Bugs: The Cursed King introduces an ally recruitment system and like Undiscovered Realms and The Traitor Soul, allows for importation of player characters from all the previous games, with no limit on how many times you can import the same save file. The recruitment system allows you to recruit player characters from other Cursed King save files too. This allows you to import multiple copies of the same save and recruit multiple copies of yourself as allies, allowing you to have an army of clones.
Traitor Soul introduces a spell to summon a monster called a Ghost Valkyrie. Ghost Valkyries, including the ones you summon, have the ability to summon their own zombies and skeletons. If you leave a dungeon area (Such as via a Town Portal) when your Ghost Valkyrie summons have their own summons active, their summons will be left behind, and should you return to the area, the left behind summons will become enemies which you can kill for XP.
Scrappy Mechanic: Muffle Magic for those heavily dependent on spell use, since it prevents you from casting spells for a while, and then you have to wait for your mana to recharge again.
, the first game's title music, and The Clergy's Lamentation