For Dark Souls on the PlayStation 3, a GameFAQs message board topic titled "Average level people beat Gaping Dragon at? It has like 1500 HP, so you can see how big of a hit that is. Both are possible without of course, but suggesting "summon help" should go without saying, as this is a multiplayer game. 1) Cut off the tail - Gaping is one of the demons, who have a weapon in his tail - Dragon King Great Axe. ". You'll find plenty of signs at this point too. Same with Gaping Dragon.

If you play the fight well, none of them will get you and additional damage from a weapon held in two hands are very useful. Quit being so damned elitist.
2) Do not think about the shield - blocking dragon's blows has no sense. The Moonlight Butterfly can be killed by almost ANY level Pyromancer or anyone with fire spells, as it has a ridiculous weakness to flame damage and one fireball will do something like 300-500 depending on your Pyromancy Flame's upgrade level. Anywho, I usually fight him between 50-60. Upon death, the Gaping Dragon drops 1 Twin Humanity, 1 Homeward Bone,1 Blighttown key, 25,000 souls and if the player cuts off his tail during battle they receive the Dragon King Greataxe.

O&S is a boss that I am pretty sure was specifically designed for co-op.