[RPG] ny official lore on the Far Realm

The Complete Divine from D&D 3.5e gives us insight into how organised religion works in D&D campaigns (TCD 130-134):

In Theocracies: The god is the head of the church, followed by most commonly high-level clerics which are above the Druids and Paladins that would worship Pelor. This is a multi-layered top-down bureaucracy with the citizens at the bottom.

In Global Churches:

A Council of highest ranking priests is at the top only superseded by the god, head priests for local temples follow in power. The church is organised in a network of temples, so clerics are often on the move and visit other temples. The common citizens of the church are taxed by the church. They are at the bottom. Such a church would act similar to a nation, but it doesn't have any land other than the temples. The highest ranking priests are almost all clerics. Some global churches have standing armies.

Both in Theocracies and in Global Churches, there will be factions that are in dispute over both secular and theological matters. Factions are called sects, and their conflicts are called schism. These sects and schism behave in a way that is suitable to that deity. So sects in the church of Pelor will not be corrupted and handle their conflicts open, most likely by trying to outperform their rivals with more acts of good.

In regional and dispersed churches:

A local high Priest, under the god, is often the local centre of power. While the structure is similar to that of global churches but every decision is for local matters. There is no network of temples with subordinates. The density of non-clerics is much higher, and overall the structure is less vertical, but the local high priest is still almost always a cleric. Dispersed churches of the same deity are commonly in conflict with other churches of the same deity, over-regionally.

In nations/worlds where churches are suppressed Cults may form:

A cult of Pelor would try to delivery acts of good while evading the notice of the (evil) suppressor. Most cults have often fewer than a hundred members with a single high priest at the head who is not necessarily a cleric. Cultists take precautions to act in secrecy and security in the form of codes, secret temples and other tools of espionage, even when they follow Pelor and would commonly act in the open.

Common lingo used throughout the recent editions of D&D, based on my experience, (2e and up) includes:

Worshippers (in order from least to most important) who consist of followers, acolytes, priests, head priests, high priest, the high council of priests and the deity/ies. There is much more specific terminology used in various places, but this (generic) language should apply universally.

If it turns out that there is no lore on gloomblades whatsoever outside of the AL adventures I've already referenced in the question, then it seems as though the lore presented in DDAL06-02 The Redemption of Kelvan is the only official source that contains any lore (since DDEP06-02 Return to White Plume Mountain just references the events of the other module, containing no additional lore).

The module states that a gloomblades are

perverted mirrors of the elven moonblades. Longswords made from a piece of frozen darkness brought from the Shadowfell [...] The sword is likely tainted by evil — reflective of Shar’s mission to unmake the world.

-- DDAL06-02 The Redemption of Kelvan, pg. 5

It also states that

the magical gloomblade, [is] a sword blessed by Shar with powers over shadow and time

-- DDAL06-02 The Redemption of Kelvan, pg. 3

And on handling the blade:

Any character picking up the sword feels a deep sense of despair and emptiness, as if all hope has drained from them. It is horrible to carry and no living soul would be able to bear it for more than a few days. The sword has no magical abilities that the characters can access at this time.

-- DDAL06-02 The Redemption of Kelvan, pg. 12

So, in summary,

gloomblades are longswords made from pieces of frozen darkness from the Shadowfell, likely tainted by evil because of the fact that they are "blessed" by Shar, although that it says "likely" implies that they might not be, though the implication is that they probably are evil. They resemble moonblades, but given that they are made from darkness from the Shadowfell, likely are not actually corrupted moonblades, but are rather created to resemble one. Gloomblades are horrible to carry, unbearable for more than a few days, since they make you feel a deep sense of despair and emptiness, as if all hope has drained from you.

At least, that's my take on the information presented in DDAL06-02 The Redemption of Kelvan.

Also, interestingly, since it seems that they aren't actual moonblades (since they were made from frozen darkness, etc), they might not actually be sentient like moonblades are, since the module doesn't explicitly say that they are, but now we're into speculation, so I'll stop here.