Berserk

It's no secret that the giant sword trope is pretty famous among video games and anime. But when you ask people what started the whole giant sword trend, they might think of Bleach or Final Fantasy. But the one series that basically started this common trend is a manga series known as Berserk

Jesus Christ, look at the size of that thing!

Berserk is an on-going Japanese is a dark fantasy manga series written by Kentaro Miura in 1989 which started as a one shot prototype manga in 1988 and it's also probably the most hardcore manga ever. Berserk has everything, gore, fighting, demons, Lovecraftian nightmares, rape, pedophilia, you name it.