I'm glad you asked, dear reader. It is true that many items within the game scale off of strength, and strength is required for greatsheilds and other weapons, including your much loved zweihander. What benefits does a DEX build confer?
-High attack speed
-high stat scaling
-variability dependent on playstyle
-being a ninja
-more varied weapon choices(I'll explain this)
-lighter equip load
-more ring options
Dex builds when done right are adaptable to all enemies and all situations

OK, so building a DEX build must mean you dump all your points in DEX right? Easy? WRONG.
These are the Three Stats of Dex Builds. Remember them. Love them. Invest in them.

DEXTERITY: Self explanitory. Your goal is 40 by SL60. All your base damage scaling will come from this. That is all you get from it, and scaling drops off after 40, so even very dedicated DEX builds don't go past 50. That being said, INVEST IN DEX FOR YOUR DEX BUILD. YOU SAID YOU WANTED ONE. And invest early. It leads to great early damage output.

ENDURANCE: "But I won't use heavy..." SHUT UP AND INVEST IN THIS! Endurance is the most important resource for DEX builds. It is more important than health. Endurance lets you wear heavy armor sure, but it also lets you swing your sword more and roll and block more effectively. you should be aiming for 25 by SL65 AT A BARE MINIMUM. I use 30 END for a SL 70 build.

VITALITY: Your armor will range from lousy to slightly less lousy unless you use Havel's Ring. This is by design. It's okay to invest in this late, because you will need it for PVP more than you will for the main game. aim for a minimum of 20 by mid game, 30 or higher depending on your specialization by SL 80. Mine will wind up with about 35-40 by SL 90. wondering why no caps were included in this section? DEAL WITH IT.

What class you start with doesn't matter right? WRONG. you are making a DEX build. your starting class does in fact matter, and it matters in the sense that it will determine which side- stats you can easily build into. decide, either as a guess or from experience, what skill you will use BESIDES the Three Stats of Dex Builds. In order to get the most out of their builds, many players like myself choose a side stat to level for the purpose of utility. Even at very high levels, these should never go past 25 AT MAXIMUM. and should only go as high as they absolutely need to for you to use the spells/weapons/ miracles you intend to use with the build. Good news? THERE ARE NO WRONG ANSWERS. Bad news? YOU CAN ONLY PICK ONE. the rest are dump stats, and you must select class accordingly.

NONE- Thats right. You just invested in the Three. High base damage, a few tiny fireball spells (if that) and you're good to go. High VIT and END make you tough to kill and offer options for poise, making you hard to topple.MAKE YOUR UNDEAD A MEDEIVAL BLADE DANCER. Start with a warrior or wanderer.

STRENGTH- Yeah. you can make a DEX bild wth some strength. MAKE YOUR UNDEAD A MEDEIVAL SAMURAI. I even invested in 14 STR to use my preferred Iaito. Add more than that, and you can use curved greatswords, keavier katanas, and mid weight halberds. Great weapon versatility. Start with a Warrior, Knight, or Bandit

INTELLIGENGE- I do this. MAKE YOUR UNDEAD A MEDEIVAL JEDI. Intelligence isn't too good for spells here, except for stealth spells magic weapon buffs. These are totally worth it as the buffed weapon will do more damage that an equally upgraded infused magic weapon. Use your brains to make your swordwork even better. Use only as much intelligence as you need for the buff you want to use late game. (Magic, Great Magic, or Crystal Magic) anything extra will increase the damage of the spell, but wont help as much as investment in the Three untill you get to the next more powerful buff spell. your Attunement will suck though, as you are paying for the sword buff only, so expect a low number of spells (2 without rings is cheap on skill points.) Start with a wanderer or theif.

ATTUNEMENT- MAKE YOUR UNDEAD A MEDEIVAL SITH. The antithesis of the intelligence side stat, you are paying for as many spells as you want. Pyromancy is your only option. But thats okay because you like setting things on fire. Your pyromancy will scale with your flame, and you will have a lot of fire spells to play with. Mostly good for catching enemies off guard and adding range without adding weight The most powerful pyromancies require two slots, but hey, Chaos Fire Whip. Start with a Pyromancer or Wanderer.

FAITH- MAKE YOUR UNDEAD A SWORDSMAN FOR JESUS. This one is slightly less specialized than the previous ones. You're going to want Darkmoon Blade or Sunlight Sword as soon as you reach Anor Londo, so invest in 30 faith and pull the remaining 5 points out of VIT. You are relying on the Gods after all. This does however, mean that you have access to all the most powerful miracles. Wrath of the Gods will let you go HAM like Paladin Leeroy wished he could. Start with a thief or knight. Clerics treat DEX as a dump stat. Idiots.

Okay, so how do you actually equip DEX builds? They're supposed to be dodgy, Right? WRO- well, actually that's about right. Load will become the single biggest bane of your existence. "But I invested in END just like you told me, I have lots of-" YOU CAN ONLY USE 25 PERCENT OF YOUR LOAD POINTS. SUCK IT UP! Large endurance values will give you access to four important things:
-Weapons with higher weights that don't suck
-Sheilds that don't suck
-Armor which doesn't suck
-the ring slots that all the fools that didn't read this guide (which doesn't suck) will be using for Havel's Ring.
PICK TWO.

Weapons with higher weights include katanas, the great scythe, curved greatswords, halberds, basically all the best weapons in the game. Curved swords tend to be lighter, weaker (quelaags furysword is powerful but finicky and the Balder Sword is a noteable exception) they all have varying weight values and you must be able to fastroll with the one you choose.

Sheilds that don't suck are basically all three weight units. The most important one of these is the Grass Crest Sheild, which you should use as long as you have the load for it and don't need a shield with special properties. The heater shield is a great alternative and should be used any time you want to transfer that one precious load point somewhere else. All shields below this (including that wooden sheild you just so proudly looted) SUCK and you are better off trading the shield for a much lighter off weapon, more armor, or heavier weapon.

Armor which doesn't suck means heavier sets of "light" armor. Not medium armor. Havels Ring will let you mix in some heavier sets for good protection. Even the warriors set is a bit on the heavy side. The wanderer's set, dingy robe, maiden robe, Xanthous set, Lords Blade set,Black Hemmed set,are all good options. The only ways to move up to some of the heavier sets is to mix and match sets or pick another option to give up. I use Painting Guardian Robe, Silver Knight Leggings, Antiquated Gloves, and an unprotected skull for a female character. Good physical and magic defense.

Ring slots often seem like the first to go. A good rule for Havel's ring is this. If you want to use the Ring of Steel Protection, use Havel's Ring of Man Up and Wear Manlier Armor. You will get better returns because you invested in endurance, but there are better options than more armor depending on your build that only rings can provide.

After selecting equipment, check your walking animation and rolling animation to make sure you are in fact fastrolling.

One of the innumerable great things about DEX builds is that you have so many varied weapon styles to choose from. In fact, DEX builds benefit from the largest choice of viable weapon options in the game. Some require strength as a side stat to use one-handed, which you shoud absolutely do for maximum versatility and tactical options. This is not a full list, just a general overview. DON'T RAGE IN THE COMMENTS.

Daggers- fast weapons like the dark silver tracer, bandit's knife, and Priscilla's dagger that have abysmally low weight and a very fast light attack. Range is miserable, and they don't break poise, but since you are a DEX build, they have another advantage. Use poison to quickly rack up status ailments and run away rougue style. All weapon buffs are more effective with these speedy weapons than with almost anything else.

Curved Swords- Curved. Swords. These things for the most part bear the benefits of low weight and better range than daggers, with a minor cost of speed. Scimitars, the Gold Tracer, and the Jagged ghost Blade are all good examples. They are surprisingly guard breaking when used two handed and offer enough damage that they are the choice weapons for more armored DEX builds.

Katanas- These things are rare. And break easy. And have higher strength requirements. AND ARE AWESOME. They have some of the highest damage output in the game as long as you repair them semi frequently, cause bleed in addition to great damage, and have amazing range and brisk attacks to boot. Their usefulness and versatility cannot be understated. Iaito is my favorite for its moveset, but most katana users prefer Uchigatana's for their higher damage output, Chaos Blade is only good for PVP (where it is the most powerful katana) because of its debuff. Washing pole is great if you built some strength into your undead. They are not too heavy either.

Curved Greatswords/ Halberds- Both of these weapon styles have large sweeping attacks, high weight, and lower speeds. Most all of them require at least 16 STR or more to use one handed. The Great Scythe is considered by many to be the most powerful weapon in the game in the right hands, though it's clunky moveset makes it less accessible. The halberd and Gargoyles Halberd are easier to use, but cost lower stat scaling and higher weight. Curved greatswords like the Flamberge and Server are heavy and require significant STR to use, but use your endurance stat more effectively when properly upgraded, and can break guards of heavy opponents, unique amongst DEX weapons.

Spears/Rapiers- Spears (Winged Spear, Partizan etc) give you range at the cost of stat scaling and are generally very quick weapons. they can also be used with a shield up. They are good fallbacks on tough bosses but generally inferior to other options. Rapiers give many of the same benefits with lower range and damage but better scaling and crits.

Balder Side Sword- A bit of an oddball for dedicated dex builds, basically a very good longsword with great dex scaling, below average durability, and low weight. a solid choice for any DEX player in any situation. Recommended but I wasn't willing to farm for it.

So you have a Dex build. And you are dying like Firekeeper maidens in a Carim Drama. Is it because you built your character wrong? is it because DEX builds suck? IS CAPTAIN RAGEQUIT A LIAR? Of course not. To fully utilize DEX builds you have to adopt a different play style. Dex builds are versatile for many reasons, one of these being that they can adapt to many different situations by changing their attack strategy.

-DODGE. This should be self explanatory. They can't kill what they can't hit. The benefit of this is that correctly timed rolls leave you with more stamina than your enemy and an immediately open hit window.Roll into your enemies attacks. IF YOU ROLL INTO WHERE HIS SWORD IS GOING TO BE YOU DID THE EXACT OPPOSITE OF DODGING. get the dark wood grain ring with a light load and you are now a dodge tank.

-BLOCK. Only on fast attacking enemies. They tend to do very low damage and so can be successfully blocked by even the grass crest shield.this also sets you up for parry. Great fallback and still doable in a DEX build.

-ATTACK. STR build are all about stunlocking and beating the enemy to a pulp. Dex builds are about attacking so ferociously that the enemy tries to back off before they even realize they arent going to be stunlocked. Most DEX weapons have a fast attack speed, with a low amount of "down" time where other players are busy picking their great hammers back up. You are not concerned with this on most of your fast attacks. Attack accordingly. Attack frequently.

BACK OFF. Your dodge skill and fast attack speed mean you can back off if you have to. Give the raging barbarian his tantrum space before you flay him alive. your running attacks are brisk, and often rangey and a great way to initiate combat with a stamina drained enemy.

CLOSE IN. Range is very important to most STR playstyles. You can dodge beautifully right next to his nose, and fast roll in for a backstab. Use your mobility to place yourself either fully out of an enemies attack range or right inside his ribcage. The middle ground will only get you killed unless you have a rangey weapon as well.

DOUBLE DOWN. Use both hands for even small weapons. This will increase their damage and make fast attacks even faster. Quick swapping between one and two handed attack styles will keep players on their toes and NPCs in line. Dodge in lieu of blocking. You are really good at it now.

GTFO. You can run faster than almost anything. This means you can get away to heal or buff against most enemies including STR players in heavy armor, and get right back to killing with full stamina.

As long as it isn't Afro, Giantdads can, in fact, be killed. It sound impossible. it isn't. It has everything to do with how you roll. Giantdads usually win by stunlocking using a zweihander (AKA the BASS CANNON) Apply buffs of choice for maximum damage and prepare to throw stunlocking right back in his face after he uses a light or heavy attack (AKA drops the BASS) by rolling over his sword behind his back. sneak a hit in while he pulls the zwei out of the ground. Remember that his heavy armor confers almost no bleed resist, poison resist, or anything that resists all the things you are good at. repeat untill he bleeds out enoug that he feels he has to heal. when he heals bleed him again. bleed goes off health percentage. so it works against health builds.

If it is Afro, Consider the possibility that you may have to retrieve your souls sometime in the near future.

-Dex builds are the most versatile builds in Dark Souls. You can do most anything with them, and tailor them to incorporate elements from most other playstyles

-The Iaito rocks. Try it. You can find it on a roof in Blighttown.

-I didn't cover bows in this guide. Thats because DEX builds only use them if the situation calls for it. I don't even equip one unless I fully intend to kill a boss with it. (Moonlight Butterfly)

-I've run through the game twice now with a DEX/INT build. For me, it feels like the most powerful build available. A lot of different people feel the same way about different builds. I'm not bashing those people. Playstyle is a personal preference and in Dark Souls as long as it works it's valid.