There are plenty of stories of cruelty of Vlad the Impaler, ruler of Wallachia (modern day Romania).
The thing is, I find that a lot of the stories are unconfirmed. It is true he impaled lots of Ottomans, "proven" thieves (the medieval courts were prone for wrongful convictions), and people who tried to overthrow him.
But I can't really find any confirmed stories of cruelty aside from those three groups. Who else did he impale? I can't believe the founder of the Dracula mythos only killed for the sake of self-preservation