There are some real historical techniques to deal with multiple enemies, you can look up the "Montante" or "Spadone" sword school in historical european martial arts (HEMA). The Montante is a way larger than normal sword used in the iberic countries that is simmilar to "Zweihanders" or "Claymores", that were used in late medieval and renassance times. Their techniques involve dealing with a highier amount of enemies and even protecting others while doing that. About the fear factor that was pointed in other answers, there are accounts of giant sword users like Pier Gerlofs Donia for exemple, that just by his own absurd size and sword size could make men shit their pants in battle, and with proper techniques not you doesn't even need to be big to use the weapons.

Video from a guy who trains this kind of sword techniques: https://www.youtube.com/watch?v=vxHaNRO705k

There are some real historical techniques to deal with multiple enemies, you can look up the "Montante" or "Spadone" sword school in historical european martial arts (HEMA). The Montante is a way larger than normal sword used in the iberic countries that is simmilar to "Zweihanders" or "Claymores", that were used in late medieval and renassance times. Their techniques involve dealing with a higher amount of enemies and even protecting others while doing that. 

About the fear factor that was pointed in other answers: there are accounts of giant sword users like Pier Gerlofs Donia for exemple, that just by his own absurd size and sword size could make men shit their pants in battle, and with proper techniques you don't even need to be big to use the weapons.

Video from a guy who trains this kind of sword techniques: 
https://www.youtube.com/watch?v=vxHaNRO705k