Anyone else beat the troll? What weapons did you use? Looking at what has worked so far, maybe it's a random BQ won weapon?
Do you remember what other weapons you took into battle other than the weapons that worked against him?
For my first victory, I only had the Hikei Grooming Brush Shield and the Illumis Dawn Bug Zapper. However, on subsequent victories, I had other weapons as well because I wanted to determine which weapon had worked/if it needed to be that combination (it didn't).
I am so, so, SO glad that you guys also won. By the end of the day yesterday, I was starting to get paranoid that I wasn't remembering some detail of my victory and was wasting the time of the entire community. |D

Do you remember which other weapons? Trying to see if there's some connection
I don't, but since my set was different each time, I doubt it's related. But there's no way I'm going to remember unfortunately, because I was just buying hordes of random tier 1 weapons (I was working under the assumption that the boss was accessible to everyone) and testing them in batches. Sorry. :c But at least one of the times, I had only those two items. And I wasn't using my battle pet, so whatever item(s) I had were definitely tier 1.

How do I get a list of weapons for each tier?
[edit] Found it. I never explore SubetaLodge much...
thank you! I am glad I won too, it was quite frustrating.
it changed once I figured out which weapon did it (which is why I thought I could only get two wins, I accidentally brought the wrong weapon one time) there was one or two battles that I brought my default set minus one spot for the knuckles.
there could be a few different riddles or hints for different batches of users maybe. it woulda been interesting to see what they came up with.
Could there be like...a hidden page somewhere on the site that tells us what the current weapon is? >_> Or something? Are there any bridges we can click under? Haha.

So, what I'm getting out of this is, do BQs, QS all loot into armoury, Try every single one of those weapons with all of your pets, and hope that one of them works? Sounds legit. Good Fun.
I don't think other users change the weapon, if I had to guess I would say everyone is assigned a weapon and it changes only when they get 5 wins edit: apparently used the goldbrand earlier that day and it did nothing, so it does change and your point is right, you may never find it unless you keep trying things over and over again, which seems like overkill to me.
Does goldbrand come from bqs? I don't remember ever getting it
- No idea. But it is a restockable weapon, which seems to be the going theory, and all the weapons you win from BQs are restockable weapons, and getting them through BQs is more fun and cheaper than restocking.
I bought them all through shop search! that's the fastest way to do them haha.
- I didn't say faster, I said more fun and cheaper :P Do you think that OPB items would be excluded? That would limit down the potential options. Did you have to use the item on the turns his weapons were broken, or did you just have to have the item in your set?
I thought maybe they could be. not sure though, with only 3 different people we know about it's hard to say. you had to use the item.
Hmm, I really hope the answer isn't using just some random weapons and being lucky :/ I hope it's one of those brain teasers where once you finally have the answer it becomes so obvious, the answer was hiding in plain sight
- Well, knowing that you have to use the item does help. And knowing that, I think it's unlikely that it would be a OPB item (cus that would just be cruel... oh look, your STS broke his weapons... and now it's gone and you've done no damage Sucks to be you!)
- I feel like if that was the case, he wouldn't be classed as impossible, or would at least have some better stats.
The hard part would be finding out the trick. It's not easy until you realize why what you did worked. The impossible aspect of him is finding out what works so it's more of a challenge for the battler and not based on pet stats. I'm hoping that's what this challenger is all about.
- But at the same time, if there's a trick to it, and one person finds it out and tells everyone... there goes all the challenge. (unless maybe they change the difficulty once it's been solved)
that's why you use two weapons at a time! and my sts does some offense because of mods I think, so it would still kill him x)
so far we have 3 seemingly unrelated items so it's looking more and more random and less likely to be a decent pattern. though who knows