Dark Souls Boss Guide Part 3 -  Hellkite Dragon, Quelaag, Stray Demon

Hellkite Dragon
This is a boss you do not want to dare fighting the first time you encounter it. To even stand a remote chance you want to have equipment with a High Fire Resistance. Sacrifice what you need to from armor and statistics to ensure that you can cap this out. You will want to either have Gold Pine Resin or a strong Lightning Weapon for attacking simply to make it more manageable to inflict damage (and a lot of it).A stock of arrows capable of dealing 200 HP damage is needed if you want to take out the tail. If inclined to do so see how much damage one arrow does then go stock to that amount. Taking out the tail will make actually fighting it much easier. You will be awarded the Drake Sword for your efforts to remove the tail.
 
Playthrough 1
For cheap tactics, stock up on a lot of arrows. You can snipe off the dragon's tail by shooting an arrow from the alcove on the far side of the bridge. After that just continue to snipe it from the far side until you inflict the total 2208 damage needed.

New Game +
With all the improved equipment it is a little more feasible to face down the Hellkite Dragon on its bridge. Still, this is best done either in the middle of the bridge or at one of the ends. This is simply to ensure that you can dodge its fire attacks which are impossible to block or evade short of having a wall between it and you. Stay close to the alcoves and stairs to ensure that you always have a way out of its fire attacks if nothing else and it loves to use those.

When the Hellkite lands on the bridge be ready for a real fight. It has a number of physical attacks which can do a lot of damage if they hit. Thankfully they can be dodged with rolling and using the Alcoves and stairs. Keep on your toes and use the Lightning Element Weapons to ensure a quick victory.
 
Quelaag
This is not a battle that will be won with blocking. You want to bring Fire Resistance to this battle. It is important to note that the Quelaag only has 3 attacks that can be blocked and all of them are better to simply evade. The rest tend to linger on the battlefield as they are Lava-based.

Playthrough 1
More than anything you will want to use the strongest weapon you have and use it two-handed. You want to close in and attack as much as possible. There is no point in being defensive in this battle, just evasive. By keeping the battle close to it, you limit its attack options and make it less likely to use its Lava Spew which blocks off parts of the battlefield as it lingers. Your odds are best by staying to either side of her head. This gets it so she will mostly use her lava attacks and her sword swings. You will be out of range of all but three of her attacks. One is a lava spew and two are attacks she rears back for. Any of these will inflict a lot of damage so keep on guard for them.

New Game +
Pull out the Fire Resist gear for this battle so you do not need to worry about its variety of Lava-based attacks. Keep in close, more to the sides, to ensure an easier fight against the Quelaag. Just start an assault and keep it going until it dies.

Stray Demon
This is another battle where you will want Fire Resistance but be sure to have defense as well. The fight is triggered so you have a little time for some last minute preparations when you enter the arena. You will find yourself back where you fought the Asylum Demon so at least you know the battlefield.

Playthrough 1
This is again a battle best at close range. While you do not need to use the Two-handed style, be wary of using it. While the Stray Demon has very few close range attacks they are very blockable and can be evaded. Almost all of its attacks have ludicrous range, making it hard to play this one out as a ranged spell caster.

New Game +
You have the gear. This is just a bigger, meaner Asylum Demon at this point. Close the distance, get it to attack to evade or block then punish it.