Bonnie, Stefan, and Damon had to defeat Katherine in order for The Vampire Diaries to come to a conclusion, and it was their deception that put an end to her long, evil life.
Although Stefan's treachery was inadvertent, it was the reason Katherine was initially discovered by the Mystic Falls founders.
If it weren't for Klaus' plans for Katherine, she would have continued to be a sweet and innocent young lady and lived out her human life.
Klaus wasn't the only vampire who felt intense animosity for the Petrova twin.
Although they had never been close, Katherine did not anticipate Elena would force the medication down her throat during their fight at Mystic Falls School.
Fans of The Vampire Diaries are aware that Katherine and Elena were similar, and the former preferred to take advantage of this.
Isobel's dishonesty demonstrated why Katherine's top rule was to have few friends. Longtime rivals Katherine and Klaus were familiars, but when the time came, Isobel delivered Katherine to Klaus.
The fact that Katherine was dealt a poor hand from the start made her a very complex villain, despite the fact that she had the potential to be evil.
Despite the fact that Katherine had been evading Klaus (and, thus, The Mikaelsons) for 500 years, they still managed to find ways to torture her; Elijah's lie was a great example of this.
Despite her complicated connection with her parents, when he killed her entire family, Klaus realised Katherine's worst nightmares.