Notes from author
Revised version of "Unlocked and Loaded" that takes things up five soul levels to introduce Pyromancy to the mix. 45 Dex maxes out Pyromancy casting speeds, and 16 Attunement gives you plenty of room to stock up on firepower.
Still the same quality build overall, focusing on playing unlocked with the Claymore, using the super stamina regen to fuel a never ending hit and run strategy that stays mobile while two-handing the Claymore. None of the armor or accessories are set in stone, only suggestions. I recommend the Bellowing Dragoncrest Ring to boost your Pyromancy if you know you're approaching an encounter where you'll be using it for certain. Most of the time, however, it's only a secondary option with a massive damage potential to other players and bosses alike.
Composite Bow pairs beautifully with Feather arrows for greater effective range and speed of flight. They do slightly less damage than Large Arrows, but Large Arrows have abysmal range with the CB, making the Feather Arrows out-damage them by a fair margin at common ranges. It's great for thinning the pack before you dash in with the Claymore, unlocked and dead-angling everything in range with the sprinting R1.
The Claymore is a monster if you get comfortable with using it almost never bothering to lock on. That's the core mechanic for this build: absolute mobility and free-aiming with the two-handed Claymore, with ranged and AOE backups.
Don't hesitate to use other weapons and gear though, 45 Dex will work fantastically with any pure Dex weapon, and allow for quick, deadly dual-wielding of your Dex weapon of choice and your Ascended flame. Try out Ricard's Rapier and the Leo Ring, or the Demon's Spear.
All-in-all, just learn to play unlocked and this build's strengths will become evident very quickly. I believe it to be totally superior to Unlocked and Loaded, which is essentially the same build with higher Endurance, no Attunement slots, and five less Dex.