Why would this NPC in Curse of Strahd ever attack Strahd?

In Curse of Strahd, there is an NPC the PC’s may encounter whose weapon explicitly does more damage when he uses it to attack Strahd.

However, said NPC states explicitly that he will not attack Strahd (emphasis mine):

The module says that the players may want to take his weapon; but its description explicitly states that the damage bonus applies when he is wielding it.

The players might try to persuade him to ally against Strahd, but he will refuse.

They might try magical compulsion, but

None of Strahd’s three goals give him a reason to go to the NPC’s location. Unless the players visit the NPC’s location, he will not leave. I suppose players could get him to venture to Strahd’s castle…

but even if the two are brought together, neither has a reason to attack the other.

The only event that will remove the thing preventing him from attacking Strahd,

will also end his life.

Any way I look at it, I can’t see a way that this NPC would ever attack Strahd, so what is the relevance of his weapon doing extra damage to Strahd when he wields it?

Has the Underdark ever been a separate plane to the Material Plane?

I play D&D 5e; I am not that familiar with the other editions of D&D. However, I’m looking for lore on the Underdark from any edition, since the settings (e.g. the Forgotten Realms) are still roughly common to most editions (even if certain events have occurred in some editions and not in others).

For context, in my own homebrew universe, I’ve decided that the Underdark is in fact another plane, although it is accessible from the Material Plane via certain tunnels and such that are like subtle portals (similar to Fey Crossings). However, this question is not about my homebrew universe (which I doubt I’ll change regardless of the outcome of this question).

I was looking into the Underdark, searching through information online and in 5e books, to see if the Underdark is a different plane or whether it is simply beneath the “surface” of the Material Plane. It seems as though it’s the latter, which means I’ll have to go to greater efforts to adapt existing adventures to my homebrew universe that were written in the Forgotten Realms, for example.

However, I believe I got my idea about the Underdark being a different plane from somewhere, so I was wondering if there have ever been any adventures or settings within D&D where the Underdark has been considered a different plane.

I’ve read online that Matt Colville has used this idea from an adventure called “Night Below”, which was apparently an old 2e adventure. I did used to watch some of his videos, so maybe that’s where I got this idea from? But even if this lead proves false, are there any adventures or settings that have ever treated the Underdark as a different plane from the Material Plane?

Did D&D 5e ever use a d3 prior to Tasha’s Cauldron of Everything?

The Path of Wild Magic Barbarian recently released in the preview for Tasha’s Cauldron of Everything has the unusual design choice of requiring a d3 roll for Bolstering Magic.

Needless to say, it’s highly unlikely that the average 5e player has a d3 die in their collection. I can’t recall any other feature that requires such an unusual die.

Was this the first time the d3 was used officially?

Total catastrophic failure, or should a GM ever allow re-rolls and do-overs?

It’s a critical moment in the game at the end of a marathon session, everyone is on the edge of their seats, and the player rolls… a 1. Evil bad guy wins, party dies, game over. As a GM, what should you do? Probably don’t structure your game to hinge on the result of a single roll, right? Well what if it was an improbable-but-possible series of bad rolls?

Should you ever let people re-roll after failing? I’m thinking no, otherwise everybody will want to re-roll after every bad outcome.

What about letting the party start over from when they first entered the room? Just for the sake of convenience and without any sort of time reversal game mechanic.

If a creature dies when under the effect of a polymorph ability, does it ever revert to its true form?

Say a creature has polymorphed itself. For instance, a dandasuka using its Change Shape ability. If it dies, will it naturally revert to its true form? If so, when? I don’t see any info about this in the Polymorph trait’s rules.

If there aren’t any cut-and-dry rules about this, does any official literature suggest one way or another?

I want to buy a used docking station for my laptop. Has there ever been a case of a docking station being a security concern?

I found a used docking station for my Dell laptop. The price is very interesting and the docking station seems to be in perfect shape. But I’m somehow worried about potential security risks. After all, you could install some kind of keylogger in the station’s firmware. Am I being paranoid here or is it possible in any way?

Why would I ever cast True Strike?

One of my players has complained several times that True Strike is a useless spell. The effect of True Strike is:

On your next turn, you gain advantage on your first attack roll against the target, provided that this spell hasn’t ended.

His argument is that casting True Strike takes your action, preventing you from attacking, but attacking twice without advantage is better than attacking once with advantage, since you still roll twice but there’s also the chance of hitting twice. This is obviously true, especially since you have to maintain concentration until your next turn to get any benefit out of the spell at all.

So why would you ever cast True Strike? Is it just a useless spell?

Have the D&D 5E designers ever done an official commentary about why they have designed certain rules the way they did?

I’m not asking for speculation or why people think the designers made the decisions they did. I’m looking to see if there’s evidence that they’ve ever done a developer commentary or something of the sorts that went into detail on their design decisions, or addressed popular questions from the community relating to that topic. Specifically, I went into this looking into official developer commentary addressing the design rationale for the true strike cantrip, but I couldn’t even find developer commentary of any kind while doing some searches with Google.

I know there’s a bit of issue with these types of questions, but I feel this is completely objective both in question and the types of answers it requests.

Was the Room of Death ever officially described?

D&D knows Mimics and their relatives, the Lurker and Trapper. They are aberrations that mimicpun intended the floor and ceiling and have been used in conjunction with a stunjelly for years to make a room that lusts for adventurers to eat. Yes the room will eat you. For example in this 2010 Screamsheet blog post, but I am very sure I have seen an older internet page that discussed the to with the stunjelly in exactly the same configuration, and after a quick search I could find Jared [von] Hindman’s 2006 article ranting about 30 years of stupid monsters, including the room of death but labeled as "Trinity of Dungeon Terror". In fact, I used his articles to build a he house filled with monsters that imitate items to try to eat you but that’s besides the point.

Has there ever been an offical Dungeons and Dragons supplement or Dragon Magazine article that employed the idea of the killer room that wants to eat you, consisting of Lurker, Trapper and Stunjelly or monsters that are virtually the same to these?1

1 – a single Greater Mimics doesn’t count. Neither does the house-sized variant unless it’s a Mimic in a Greater Mimic in a House Hunter Mimic. It must be 3 monsters.