Petrus takes a bath

I've managed to beat Elpuri and Oree (and teleport away from the mage room) with natural limbs, which is pretty nice. I'm not quite confident enough in this character's stats to try fighting Petrus. There are methods of killing Petrus with mustard gas in 0.50.5; however, only one gas grenade spawned for this character, and it was on top of a mine. Ugh.
I spent all my wishes getting cloning charges and scrolls of change material. I couldn't even spare a wish for an amulet of elemental protection, let alone a grenade.
Before going for the shirt I tried to assassinate Petrus with just explosives - tamed all of the cathedral dwarves, stacked their backpacks on one of them, along with a few wands of lightning, fireballs, striking, and the only wand of acid rain in the game. When I aggravated Zak the kamikaze dwarf of Valpurus, he died partway through the explosion, and dropped all the unexploded items on the floor. They were whisked away to the dwarf room, partly intact - the wand of acid rain broke.
So, no mustard gas, and explosives are prone to failure. One option would be to give all the explosives to a friendly adamant golem and have a betrayed dwarf trigger them, but that can wait for another time. Looking at Petrus's equipment (and his entry in char.dat) reveals a total lack of acid resistance. Probably as a result of watching Orphan Black before going to sleep, I decided to try to give Petrus an acid bath.
Mellis spawns sulphuric acid rather often, and normally I dispose of it by dipping mithril weapons in it. This character managed to gather 53 empty bottles, and 34 more filled with disposable fluids. Based on my experiences making the sumo wrestler stand in vomit, my expectation was that the acid would eat through his boots of agility and destroy his legs, and the rest of his gear (which is all acid-proof) would protect him from further acid damage. I would then melee him with slightly more confidence.
A quick test in wizard mode revealed that this was very much not the case.
Ingredients:
* 45 bottles of sulphuric acid
* Tame armless rookie dark knight
* 3 Kamikaze dwarves of Valpurus
* 3 backpacks full of gunpowder
* Wand of slow
Initial experiments with an adamant golem showed that a broken bottle doesn't leave any fluid on adjacent tiles, so the acid would have to be moved under Petrus. While searching this forum for previous attempts to dissolve Petrus, I read another poster's experience getting an armless rookie dark knight to kick mines safely, and found that the same creature could kick a bottle of acid for 6 tiles without breaking it. I managed to get 37 bottles under Petrus's feet before he suddenly started kicking them a few tiles further. Facepalm.
Anyway, the stage was set. I brought 3 dwarves into the throne room, named one Zak and gave him the backpacks belonging to the other two. Manoeuvred them a bit, aggravated Zak and let him explode on the others.
The plan seemed to be sound; all 37 bottles broke, and all of Petrus's equipment was covered. A stethoscope showed that Petrus had also lost a little health. However, the stethoscope was in slot H when I tried to apply it. How terrible is that? I nipped outside the cathedral quickly so that I could drop the other tools and use a stethoscope from slot A. Much better.

When I came back Petrus was already dead. Even his dissolvable boots survived longer than him.
Repeating the experiment showed that it took less than 2 minutes for his head to be destroyed. This is clearly a winning plan.

To implement this in the real game, I'll need to spend a lot of time praying to Mellis, and probably stay out of the dungeon so that I don't get a nasty surprise from Sherarax or Ischaldirh. I've managed to disarm a veteran guard, whose kick seems to move a full bottle 6 tiles. I'd prefer a golem that can't train its leg strength, but I'll make do. I'll also have to clear all my other pets out of Attnam so that they don't interfere with the bottle-kicking phase.

I'll be back later with news of success or failure.

Mellis gave me a lot of ommel fluids in addition to the 37 bottles of acid, and the process took about 10 days, during which I liberated Tweraif.
I filled a chest with gold helmets and metal armour, and used it to overload the tamed guard, fixing him in place next to Petrus. I gave only one backpack to the dwarf, in case I needed to try again.
My wand of slow was probably depleted, so I angered him by throwing a ring of teleportation. Took a lot of effort to get him in a good spot.
After the explosion (at 11:37), only 23 bottles were broken (14 remained intact). It wasn't the dwarf's fault! I gave him too few explosives!
Nevertheless, Petrus's head was destroyed on schedule (he died at 11:40).
I had sold 14 books of Valpurus to the library during the game, and it took about 5 of them to become champion and win.

Final score: 1161540

Disadvantages:
* Requires a lot of bottles.
* Requires Mellis, who sometimes isn't available until well into GC.
* Requires a lot of time to fill the bottles with acid.
* Requires a weak humanoid pet to be disarmed without dying.
* Requires a means of taming dwarves.
* Requires pets to be cleared out of Attnam during setup.
* You don't get the Justifer without angering Attnam.
Advantages:
* Doesn't require gas grenades or mines to be saved.
* Doesn't require good equipment, stats, or even fire resistance (as the explosion can be small).
* Doesn't anger Attnam.
* 23 is an upper bound on the bottles required - the real number is probably much less.
* Time can be saved if you start collecting or cloning acid bottles early.
* Cruentus provides infinite bottles, if you can pray to both him and Mellis safely.
* Dulcis provides free taming items, if you can pray to both her and Mellis (and Cruentus?) safely.

Massacre details:
A lot of things died while polymorphed by my GEF chameleon whip.
The enner beast died from about 2 direct hits by a wand of fireballs.
Genetrix Vesana was killed by a holy handgrenade, because I was a total wimp when I reached UT3.
Golgor Dhan was killed by repeated zaps from a wand of striking, mostly while distracted attacking a couple of pets.
Guugzamesh showed up far too late to present a threat.
Oree died about as easily as you'd expect.
Richel Decos took more than one hit to kill! Well done to him.
Rondol spawned in GC6 and I forgot him, which had me angsting about the lack of wands of polymorph for quite a while.
Found two valpurium golems! They both got polymorphed before running out of health.
Xinroch showed up in GC10, way too late to be a concern.
Zolku and the banana grower encourager were killed by wolves.
Elpuri was fought by Vladimir and Alvin the angel of Silva, who got the killing blow.
Alvin went on to kill ZQ-29, and I didn't realise until I checked Alvin's equipment and found a spider silk armour. Even then it took a thorough search to find the loot.
Alvin was killed by Ur-Khan, whom I kited to death in 5-10 hits.
No Ischaldirh or Sherarax.
Ivan was killed by a bronze golem while polymorphed into a werewolf in GC8. Silly Ivan.
The sumo wrestler... guess.
Excel's puppy Menchi was killed on the very first level by a zombie of a kamikaze dwarf of Valpurus.

Inventory follows, minus the strongbox full of nonexciting wands:
I never had enough spare cloning charges to get permanent haste and invisibility, and after having to buy books of Valpurus back from the library that was probably for the best.
The stack of whips was for disposing of non-acid liquids given by Mellis.
There's also a large chest at the entrance to Attnam, full of... just about everything that I hoovered up from the dungeon.

Nice. Why does it matter that the stethoscope was in slot H instead of A?

It doesn't. I just like to have my tools in order so that I don't have to look at the list when applying one.
Also, I use the nethack keys on this computer, and H is under the right hand. Checking the inventory screen, it seems I actually moved it to D. AD is a much more fluent sequence of keypresses than AH, which suits a tool that sees a lot of use.

The reason for that would be an increase in leg strength.

Nice win regardless!

That's why I would have preferred a balsa golem for the job. Unfortunately golem scrolls are scarce, and if I accidentally killed it I wouldn't be able to resurrect it without arms.
When I tried it for real I only dropped two bottles at a time, so that the waste would be minimised if Terry's leg strength did increase during the process.

Wow. You're scary good at this game. I've only ever managed an Elpuri victory.

Well done, that's an awesome way to eke out the Petrus kill with little to no extra resources! I'd most likely have just ended the run there with a knight win.

Is there a reason you kept extra wands of cloning instead of breaking them for more clones? Moreover, seeing as both your weapons could be cloned, wouldn't it have made more sense to focus all enchantment scrolls and skill gains on one weapon instead of spreading it over two weapon types? I could see it as a way to reduce limb hits in the late game, if that's what you were going for.

That why i stack them outside the cathedral on top of an octiron/adamant trap and wait for him to come out.

Because... I... forgot. :3
Also, experience with player clones has showed me that they always have leprosy and it's difficult to make them drink antidote liquid (I guess that's because I was satiated when those clones were made), so I have a slight aversion to making them.
Heh, yeah, probably. Earlier on in the game I was dual-wielding flaming swords, and focussing enchantments on one of them with the intention of cloning it for the endgame. Then a +5 chameleon whip showed up in the dungeon and turned out to be better than the unenchanted sword. They made a good combo and I wasn't in a hurry to switch to dual whips.
I think the scroll I used to change it to GEF came from the last cloning charge, which meant that the only way to clone the whip was by breaking a wand, which I had forgotten to do.
Yeah, I've done it that way once, but there's a lot that can go wrong in the time it takes Petrus to leave the cathedral. And if you don't have enough explosives to kill him twice, you're back to fighting him (and an archangel) fairly. I've seen that archangel kill Sherarax.
It is possible to make Petrus leave the cathedral if a hostile genie survives the guards and shopkeepers long enough, but that seems an even more unreliable way of getting him into traps. Another option would be to spawn a dangerous enemy in the catacombs and lead it into town. Perhaps with a unique corpse, two wands of resurrection, a wand of teleport, and a mine.

I love the sound of that last idea. You'd have to make it powerful enough to survive the shopkeepers and guards as well.

So you drop your corpse, point the wand of resurrection, give it some healing liquid, equip it with its original weapons and armor, then kick it and run!

Then just picture the faces of the townspeople as you emerge from the catacombs with Golgor Dhan hot on your heels

Attnam won't be hostile to a mere betrayed pet - the wand of resurrection would have to be triggered (broken) by something other than the player, such as a mine or betrayed dwarf.

I love that this win is in the dev version! Good thinking using the acid explosion, it must've taken some patience and careful planning. Did you get hassled by the fire system? Frightened by ghosts?
Did you find the application stable enough or were there moments when you feared the game might break at any minute?

After a couple of days I became impatient enough to cut all the other gods out of my prayer routine; that sped the process up a lot. Locking the kamikaze dwarf's target in place made the final step much less frustrating, too.
The fire system makes me a lot more careful with scrolls and doors. If I let equipment get burned, Loricatus is liable to repair it instead of rolling the dice for adamant equipment. Mellis's free fluids become even more important for dousing things quickly. Sometimes I have a burning item with a tiny bit of liquid on it, and I have to wait for that to evaporate before I can soak it properly. Dwarves' books are especially prone to this. Silva's rain is very unreliable for putting out fires, especially of inventory items. If I'm forced to use it, I seem to have more success dropping items on the floor than wearing them. More than once I've openly carried scrolls of detect/teleport on GC5, and the enner beast has set off an explosion that instantly destroys it. Very annoying
The new ghost visuals are good; it's nice to know what they are without having to examine them. Undead versions of veteran dwarves and high-level mistresses are brutal, and can appear to a character without equipment in UT1. :S
Most of the crashes I've experienced are reported on github and avoidable by the user. Activating fullscreen mode, talking to Ivan, and digging while hungry are all avoidable.
One exception is a crash that I get when a Windows 7 UAC dialogue opens. I probably ought to just uninstall Java.

... Why doesn't Petrus wear a helmet?

http://tvtropes.org/pmwiki/pmwiki.php/Main/HelmetsAreHardlyH...

Yep, the rain works best when you lay the burning items on the floor, individually and not stacked. I don't think the rain ever makes it to your inventory. Not sure how this can be improved.
I know about not being able to dip things with fluid already on them. I don't know how best to tackle that. Have you tried vomiting on it?

I think your pack should be fairly waterproof so it's fine if the rain doesn't get to items inside it.

About the hand surgery part - wouldn't it be possible to equip your pet with two shields? They should only kick you, then.