Divine Weapon-You will want one of these to keep skeletons dead in the catacombs otherwise they revive themselves,also Faith stat is suppose to influence the damage output of these weapons so it is perfect for a high faith character build.
To create a Divine Weapon from scratch you need to begin with a standard weapon ( one that you can appply pine resin to otherwise it is unique and will not work ), Some divine weapons can be found throughout the game this will save you some materials in the ascension process and souls.
First off you will need to find the Divine Ember which is located in the Darkroot Forest (See first vid below for location Credit to Marce1024 for the vid) and give this item to Andre of Astora,This allows you to create a Divine Weapon.Then you will require the Large Divine Ember which is located in the Tomb of Giants ( See second vid below for location and credit to B4O4S4) this you also give to Andre of Astora, this ember allows you to finish upgrading the Divine weapon from +5 to +10 finally netting you the achievement.
In order to complete the Divine weapon you will ultimately require 9 Titanite shards , 10 Large Green Titanite shards , 9 Chunks of White Titanite and 1 White Titanite Slab
White Titanite Chunks - Kill the smaller skeleton towers in the pit that Patches kicks you in at the tomb of the giants but they have a low drop rate , The best spot for farming all chunks is the end of the game at the Kiln of the First Flame , all the Black knights there are respawnable and have a 100% chunk drop rate.
White Titanite Slab - In the room where Pinwheel servants were just before the boss in the Tomb of the Giants.(see vid below)
Here is a Chart which was created by an unknown so credit to whoever they are.
When farming it is best to have the Gold Covetous Serpant Ring equipped and 30 humanity for a maximum drop rate of 410.
TRICK-To get the achievement without using your items simply fully upgrade the item in one shot and wait until the achievement pops WITHOUT leaving the upgrade window thus not allowing the game to save the data then simply turn off the game and turn back on.