Its flamelurkers red hot demon souls you need, this gives ed the extra heat needed to forge sharp, , crescent, cutting, crushing, dragon and blessed weapons.
There are basically four types of weapons in this game.
A stand weapon that can be upgraded to +10 using standard mineral ores. These weapons have a low to medium damage stat.
Then theres are the magic weapons which can be upgraded to +5 using special ores such as faintstone or dragonstone. These will have the standard damage plus a bonus damage stat based on a particular character stat such as faith or magic.
Then there are the magic weapons that are upgradable only through the rare colourless demon souls, these tend to start of strong and any upgrades usually offer a secondary benefit such as magic regeneration or health regeneration.
Lastly there are the unique and non upgradable weapons such as a scraping spear, these are forged from a high base stat weapon (in this case a spear +7 and a unique demons soul)