Notes from author
For those who do not like the greatsword or do not like the claymore, the weapons Longsword, Broadsword, Bastard Sword, Zweihander, and Halberd are also good options. This is mostly for roleplay purposes, but it also is a good build for Fire Knights as far as I know. The preferred starting class is Warrior, as you need higher dexterity and strength to be at the lowest level that I know. You can use any spells that are Pyromancy, but the preferred spells are listed in the build. You must use Astora Knight Armor, but the helmet is open for any type of helm or headgear. Preferably light headgear. Faith needs to be 30, to allow for greater protection against the magic of other spellcasters, and put in a couple of points into intelligence just to be safe. You must use either Charcoal Resin or Fire Enchantments for weapons, regardless of what the highest elemental stat is for the weapon.