10 Game Of Thrones Scenes WAY More Brutal In The Books
2. Euron's Return To The Iron Islands
Euron was woefully underutilised in the show, what we got was the palest imitation of one of the most maniacal and sinister villains ever written. He's portrayed as a crazed pirate, with a sarcastic and crude sense of humour, who has very little impact on the plot. In the book he's far more evil and actions will likely change the history of Westeros; comparing him to the Devil wouldn't do him justice.
He turns up in season six, and almost immediately is endorsed by his younger brother Aeron, who performs a ritualistic drowning and offers him the Driftwood Crown. But this was an incredibly simplified and peaceful version of the book events.
Although Euron does take power pretty quickly, his brother Aeron opposes him. Euron has him imprisoned, and tortured by feeding him the hallucinogenic potion, Shade of the Evening. This causes Aeron to see terrible visions of his brother as a strange half-kraken-god with all the other gods impaled on stakes around him. It also triggers Aeron's memories of being repeatedly molested by Euron as a young child. Aeron is eventually forced to serve Euron, but it's implied he will be offered as a human sacrifice.
The last we saw of the Drowned Priest he was tied to the prow of a ship next to a naked and pregnant former bed slave, who's had her tongue removed.