AbdulAlhazred
Legend
Well, my level 12+ AD&D Ranger, with some really stupid powerful items, was able to WADE THROUGH A SEA OF DEMONS and due to vampiric regeneration GAIN hit points every round (and there was no limit to how many you could get that way, lol). It did require some of the most powerful items in the game though. Still, it was pretty amusing, until the DM started wondering what having 5000 demon hit points would do to you...The one man army concept had some expression in early AD&D (though it almost never happened in practice) and also imagery of Conan or Elric Standing on heaps but it is much older go back to myths of Cu Chulainn who was described as standing on a chariot and using his weaponry to mow through the hordes of enemies on all sides as the chariot drove through. And is now vividly all over the place in a lot of modern fantasy yes some arguably D&D inspired and coming from Asia. A recent King Arthur movie had an Excalibur super charged Arthur doing something which felt like time dilation and the super sonic movement dave mentioned to attack hordes of enemies similar to the sword mage ability he also kicked up huge amounts of scenery in the process Yes in the story it was a magic item but to build that in 4e I would very much use a multiclass into the Swordmage for that paragon path and attribute the power to his special relationship with the artifact (he had to learn to control it).
Cuh Chulaine was actually presented as an example fighter in the 2e PHB and his story was very much about him being a prodigal youth learn at a very early age faster and better than those who taught him many "feats", arguably this is where D&D got the word feat too.