Diablo III has two achievements that involve fighting bosses in nothing but your skivvies: Naked Lust and The Hero's New Clothes.
Obviously, clothes are kinda important.
Which class is best at slaying monsters in the nude? If you're seeking to complete this achievement in multiplayer, does everyone have to strip down, or just you?
And perhaps most importantly, do weapons count, or are we going to be punching Diablo to death?
I can't see any requirement to do this solo, nor that all your party members have to be naked as well.
In which case it would be simple: find a friend (or two or three), join up, and let them kill the boss with their gear. Probably you will die during the fight, but that won't stop you from scoring achievements.
I haven't tried this out yet, so this is pure speculation.
Update: yx. has tried it, and confirms it works (see comments). Thanks!
I did the Cydaea achievement solo on a Demon hunter, and it is about as annoying as you'd imagine. First off, you only need to take off your gear at the end (obviously). Here's how I did it:
Take a decently geared DPS companion. Mine was at ~500 DPS.
Fight like normal, get her down really low (<10k). Then retreat to the other side of the map.
Start taking off equipment. (Do NOT drop it on the ground.) This is annoying because you have to go into your inventory and you're pretty much blind the entire time, hence the retreating part. If Cydaea enters an add phase (lots of spiders spawning and Cydaea vanishes) don't stand still. You need to move and kill them ASAP.
Keep in mind ANYTHING will oneshot you when you're naked. Smoke Screen really helped me.
Once you're naked and there are no spiders alive, move your companion within range of Cydaea and hope they target her. She will spawn a small amount of adds even outside the adds phase, and she likes to retreat behind them, causing your follower to target them instead.
If Cydaea isn't dead before the next add phase (about ~30 sec between them), put weapon back on and kill the adds while avoiding them. If you don't do this, the adds will pile up fast. When the coast is clear, unequip weapon and move back to Claudia Black.
Rinse repeat
It took me about 15 tries, mainly because spiders can spawn right under you and oneshot you in a heartbeat when you're naked (Keep moving!). It might be easier in coop, with 1 player handling adds/optional ressing, and the other hurting her, but you won't have the follower and your naked DPS is roughly...10.
The other bosses? I haven't tried them yet, but they might actually be easier, because there's no adds, though having to dodge stuff (Belial...) while taking off your gear is probably the trickiest part.
I'm yet to attempt it but a Witch Doctor would be the most obvious solution for these achievements. Using his/her pets to take the brunt of the hits and do DPS can largely be equipment agnostic, as opposed to Barbarians and Demon Hunters for example, who would both significantly suffer if they are unable to equip a weapon.
Select your skills and runes such that they all either boost your summons or your own survivability (since you'll have no armour), and it would give you the best chance out of all the classes to manage this achievement.
I haven't tried to get that achievement yet, but your follower should be able to help you with this.
Here's how I would do it:
Warning: Don't drop your gear to the ground. Use your inventory instead! If the boss kills you (which is quite possible since you're not protected by any gear), you'll lose all your items. This is because the boss area will respawn if you enter it again and all your stuff will be gone.
If you're a high level Demon Hunter, start a game and:
Then get to the boss, drop a sentry and avoid the boss' attacks until the sentry despawns. Repeat. Also if you try this with Diablo, remember to punch him for another achievement, "Punch Diablo".
It may not be the best DH approach, but the best I can think of with no abilities based on a % of weapon damage.
You need to be the one who deals the killing blow.
I just tried this for fun with a friend who was bored. We went after Cydaea first, and after he killed her, I didn't get the Naked Lust achievement.
Solo it would be kind of difficult, because companions do no damage, and you're companion would end up killing it before you do if it's equipped. You'd also want someone to keep the hate off you while you're attempting to kill these bosses so...
Barbarians have twice the defensive capabilities of all other classes (save One other, with similarly doubled defense.) however they are slower than say the Monk or DH. Gauge your choice of class per individual boss. This means a level ~55 character of each of the classes, but if you're bothering with banner points at all you will have to develope a level 60 in each class anyway eventually. Some bosses require less speed, and so a Barbarian would be good on these, while those who require reaction time would want a DH, with spawns a DH or Magician. I have always felt the witch doctor to be a stellar backup in a party, but slower/AI dependent so not easy to use in most boss battles. An Inferno WD would be a miracle for me.
Another method is to use long-duration spells, such as the Demon Hunter's Chakram#Shuriken Cloud. Cast it before entering the room, then strip naked, and you've got two minutes to do damage with the cloud by standing next to the boss. I don't think it's actually necessary to start off the fight naked, but it means you don't need to fuss about in your inventory while dodging attacks.
Stun Grenades also help a lot versus the Butcher and Azmodan: They're big enough that all three of the grenades hit, so you can get pretty close to perma-stunning them, even with only a 25% chance per grenade. This gives you time for your shuriken and your follower to slowly kill them.
As of season 23 the achievement is no longer there.
I was interested in the challenge so I just killed Cydaea without any items as DH (the whole fight without even a potion equipped; so just the standard issue). It's moot, but here's how I did it. It was hard, but I have my follower pretty geared out (over 25k dex).. I took grenades as primary and the grenadier and cheat death passives. I chose impale as the spender. Took vengeance, shadow form, and animal companion (wolf ofc). Don't stand in anything. Run laps while your follower does the dirty work..
I don't think that it is possible to kill the bosses without gear.
I think you just need to kill the boss without gear, not to be naked the whole fight. Because it would probably take hours to beat a boss with just your fist (or just the weapon).
What you can do is to get the boss low health(really low health) then unequip everything and let your companion do the rest, but this is still quite hard to do since you will probably get oneshotted by any hit and the companions do nearly no damage.
