What is Lunar Entropy?

In a prior post, I went over how various editions ruled the "Sundering", the transformation into Selenim. Mostly verily clunkily, as usual for this game. It turns out that I forgot something, not that I'm surprised given how incoherent and scattered the Nephilim rules are in every single edition. 

Bizarrely, 5e La Toison d'Or p127 introduces the rules for "Lunar Entropy" rather than the 5e Selenim book released prior. The latter lazily copyedited the text from the 1e supplement, ignoring every supplement published since, and which wasn't properly adapted to match the 5e rules. By contrast, the new Lunar Entropy is written in line with the other rules for Downfalls of Khaiba, Narcosis and Shouit. The text doesn't explain if this supersedes the older rule or not, but for simplicity's sake I will assume so. 

Recap of Lunar Entropy rules

Lunar Entropy "degrees" are gained by:

• Accepting a physical consequence from a Black Moon creature in an environment saturated with BMK requires you to pass a test in opposition between the degree of the consequence and its dominant Ka or risk receiving a degree of Lunar Entropy. 
• Performing a fumble on a Moon-Ka test in a BMK-saturated environment, whether as a magic effect or using an approach, causes two degrees of Lunar Entropy. 
• Experiencing a disembodiment in the middle of a Black Moon Realm always results in a minimum of three degrees of Lunar Entropy.

As with other Downfalls (i.e. Khaiba, Narcosis and Shouit), Lunar Entropy is divided into four steps based on the degrees (1-4, 5-7, 8-9, 10):

1. The Nephilim seem to lose themselves at times in strange daydreams that cause them to lose track of their actions or thoughts. This often happens near a graveyard where he seems to hear the dead humming.
2. The Nephilim become obsessed with their Moon-Ka and are reluctant to use their other Ka. Doing so causes him a minor magical consequence.
3. The Nephilim became obsessed with the Black Moon. He returns to wander like a lost soul around the place where his contamination was born. The Nephilim is no longer playable and must be given to the GM.
4. His Ka other than his Moon-Ka detach from his Pentacle inflicting excruciating pain on the Nephilim. Without the intervention of a Selenim "midwife", the Nephilim have (13 − Moon-Ka) x 10% chance of changing irretrievably into Khaiba. If this test is successful, he permanently transforms into Selenim.

Lunar Entropy doubles as a Khaiba form. A Nephilim cannot have more than three lines of Downfalls in 5e, so Lunar Entropy displaces any existing Khaiba if it overwhelms the latter during the course of a single episode.

My commentary

Lunar Entropy is consistent with 2e's Le Ka and 3e's The Players' Book in that all Nephilim may contract it, not just Onirim. Conversely, Lunar Entropy afflicts all Nephilim equally without regard for their Moon-Ka level. It only makes them focus on their Moon-Ka by making other Ka harder to use. This odd because it reframes one of the key reasons Onirim are widely distrusted: previously Moon-Ka was distrusted because it was more susceptible to Lunar Entropy (which led to the Tutelage of Four Elements amputating the lunar branch from their victims!), but here those with higher Moon-Ka are at an advantage compared to other contaminated Nephilim because they're more reliant on Moon Spells in the first place!

Anyway, overall I like this addition in terms of the basic idea if not the execution. The lore has always implied that Black Moon contamination had a haunting morbid psychological effect, but no rules were ever given. The most overt examples are Baron Samedi's backstory about his Black Moon contamination developing its own personality (as explained in the campaign Loa), and the note in the Codex des Selenim explicitly stating that this contamination develops sentience which becomes that of the Imago. It's nice for the rules to finally reflect that, even if they don't reflect anything else published since 1e. :(

This design also solves two problems I noticed with the 3e rules:

• Contrary to prior editions a Nephilim only risked Sundering when confronted with large concentrations of Black Moon-Ka, like entering a Realm or being subject to certain Composition Executions (i.e. third circle black summoning spells). So the contamination could be safely ignored by deliberately avoiding those kinds of situations, which seemed pretty rare to begin with. The psychological compulsions inflicted by 5e's Lunar Entropy address that by seducing the Nephilim to seek out such conditions.
• The Players' Book states Nephilim cannot survive having fewer than four branches, a Cross of Ka for Cruxim. But Black Moon contamination is able to strip branches away until only Moon-Ka remains without causing the Nephilim to dissolve into the magic fields, and this contradiction is never addressed: any potential "Trixim" and "Dixim" simply don't exist in the lore. 5e's Lunar Entropy solves this by simply condensing this process into two steps: initially the Nephilim finds it harder to use Ka other than Moon, then finally all the branches other than Moon-Ka are removed at once.

Now... how would I retrofit that to 3e?