For those that don't know, the Dragon Greatsword is a weapon you can get from The Everlasting Dragon in Ash Lake by cutting off it's tail, this doesn't make the dragon hostile with you and does not break your covenant if you are in it.
This sword broke the game for me, every boss fight was a cake-walk after I got this sword and I think it ruined the game for me, at least for now. I upgraded it to +4 and all I had to do was 2H it and use the R2 special to kill every boss.
Anyone else ?
*Edit* Just to clarify, I have beaten the entire game. I can't seem to find anyone who doesn't think this weapon is a joke in terms of power yet.