I've played the shit out of Dark Souls II, so I have, out of laughs, obtained all possible armor and weaponry in the game and I've used it to cosplay quite a bit.
Could give some pieces of advice on sets for the cosplays and how they performed, but stat builds aren't my strong point.
So here are some cosplay "builds" I've constructed.
<spoiler=The Pursuer>
The Pursuer
1 Elite Knight Helmet
1 Steel Chest
1 Steel Gauntlets
1 Steel Leggings
1 Pursuer's Ultra Greatsword
1 Pursuer's Greatshield
Tactical Evaluation: Since I am personally bad with using heavy weaponry, and the same with shields in general, I found this build to be completely useless in PvP, however somewhat effective in PvE. Of course, you could do much better in both PvP and PvE with normal armor and weaponry.
Looks badass however, and will definitely make you smirk for a good 5 minutes of gameplay.
<spoiler=Ninja>
Ninja
1 Thief Mask
1 Shadow Top
1 Black Leather Gloves
1 Varangian Leggings
2 Cool weapons of your choice that you think a ninja would utilize, or more (I recommend Berserker Blade (katana, rare drop) Shadow Dagger (dagger, rare drop) and Monastery Schmitar (schmitar, rare drop) and a good, quick bow.)
Tactical Evaluation: If you have 8 in Vitality, and you use Ring of Blades+2 and Flynn's Ring, you gain 100 damage with ALL weaponry in the Physical Damage category. With the addition of a good amount of dex and str, it's not unusual to see 200+ damage on pretty much any weapon you pick up. Since this set weighs barely anything, you can still roll quite conveniently as long as you don't choose to wield heavy weaponry or shields. I find this to be REALLY good in PvP and PvE, and is one of my favorite builds.
<spoiler=The Peasant>
The Peasant
1 Peasant Hat
1 Peasant Torso
1 Peasant Gloves / Tseldora Gloves
1 Peasant Boots / Tseldora Leggings
1 Pick-axe
1 Hand Axe
1 Scythe
Tactical Evaluation: Since this build barely takes up weight, the Ring of Blades + Flynn's Ring combo at 8 Vitality adds a serious punch to your frail peasant arms. You might also be surprised how well invaders can be persuaded to let you live if you simply act of as a mere humble peasant. I have on several occasions stood in an active PvP hotspot, got invaded by someone random, and conviced him to start mining some wall with me when I handed him a spare pick-axe of mine.
It's not supposed to be good in either PvP nor PvE, but it is very good for a laugh or two with random people.
<spoiler=The Tauren>
The Tauren
1 Minotaur Helm
1 Drakekeeper Armor
1 Drakekeeper Gauntlets
1 Executioner's Leggings
1 Smelter Hammer (requires 70 strength to wield, and more to Power Wield with another weapon if you are so daring)
Tactical Evaluation: Looks cool, feels cool, and it deals ludicrous amounts of damage, even without enchantments. I would not recommend it for PvP (because I simply cannot recommend what I cannot use. If you are experienced with great hammers, go for it!), but it actually packs a punch in PvE. This can't utilize Flynn's Ring for obvious reasons. The Smelter Hammer alone weighs 35 points, which will make you fat roll at 8 vit.
You could also switch Executioner's Leggnings to something else, like Steel Leggings or Drakekeeper Leggings, but I didn't want to look like a freaking statue - a tauren is a living, fictional being and should have some skin shown to indicate this. That's why I recommend Executioner's Leggings.
Also, try using the parry move with the hammer. You won't believe your eyes, most likely.
<spoiler=Bloodborne>
Bloodborne
1 Hunter's Hat/Durgo's Hat
1 Robe of Judgment
1 Black Leather Gloves
1 Black Leggings/Llellynn Shoes
1 Butcher's Axe
1 Nothced Whip/Old Whip
1 Red Rust Schmitar
Tactical Evaluation: After seeing the Bloodborne trailer and some other videos talking about it, I found some inspiration to make a proper depiction of this Bloodborne character you see, but there is one problem - shotguns do not exist in DKs II, and crossbows/bows proved to be an extremely poor substitute, as they take ages to reload, and do not necessarily stun your opponent. That is why I decided to use a whip in my offhand instead to stun my opponent and then slice the living crap out of them. This build proved to be very effective in PvP and PvE. You can use the Red Rust Schmitar to parry opponents or make a quick attack on nearby foes (just like the whip, it acts like a stun that Bloodborne utilizes)
It looks cool as shit and can utilize the RoB+2 and FR combo quite nicely.
I could post some more cosplays I've attempted, but they aren't anything special nor interesting and just copied the appearances of other bosses or NPC's. It's just that these 5 sticks out to me.
If you don't know where some of these items are, you could search these links for information on how to obtain them:
http://darksouls2.wiki.fextralife.com/Weapons
http://darksouls2.wiki.fextralife.com/Armor