First of all, you don't need to be level 50 for the "best" of anything. Nearly every item in the game is maxed at level 30 or better (including that sword.)
Secondly, while it's an amusing toy, I think it may prove less useful at high level than some of the other weapons you could carry, including some that do more damage.
Thirdly, all of the quest-line content becomes greatly more difficult at high level, especially if you have leveled quickly, and haven't developed your fighting skills and equipment in parallel with your advancement.
yea but i read that the sword is the best at level 50 because on the site it shows it is best at level 30+ so i looked it up and lots of ppl said lvl 50 and it is the best weapon in the game at that level it has the highest damage of all swords
I think you've got some slight misinformation there. Level 30+ means that you get the maxed version at level 30 or above.
I believe that Goldbrand, which can be gotten at level 20, does the same amount of damage per strike as the maxed Dusk/dawnfang, but is faster, meaning it will do more damage over time. I also believe that the 25+ version of Chillrend can do more damage over the course of several hits.
i read on the wiki that the dawnfang/duskfang is the best weapon in the game
Personally I think you're becoming a little too fixated on finding the "best" equipment. This isn't an MMO situation where you need the best gear or else you'll get kicked out of a raid. I think you'd be better off relaxing and enjoying the game.
Just my opinion.