Book of the Abyss Lector

Ego sum fatus

Abyssi ergo mundo

Ex culmine lucis

IN MAGNO

Obscuritatis lux

Se effundat in

Mentes abysso

Translation notes

Ego sum - I am

Fātus Abyssi - word/oracle/prophecy of the Abyss (abyssi = genitive singular of Abyssus)

Comment: fātus sum can also mean “I have spoken” (perfect indicative singular of “for”), however then the “abyssi” would be without a proper noun to refer to (grammar could allow that, but “for” is a defective deponent and my grammar knowledge does not reach far enough to tell for certain. The meaning does not change regardless though).

Ergo - therefore, thus, hence

Mundo - I clean/cleanse (first person singular) - lacks an object, so not sure

              world/universe/mankind (nominative singular > subject) - lacks a verb so not  

              sure

Ex culmine lucis - from/out of (ex needs ablative) the top/roof/summit/peak/height (culmine is ablative singular of culmen) of the light (genitive singular of lūx). Can’t be dative or ablative plural of lūcus (grove) for grammar reasons.

In magno - in/into [the] big/great/important (magno dative masculine/neuter singular or ablative masculine/neuter singular of magnus).

Comment: magno has nothing to refer to in this sentence as it would need a dative or ablative female. The “abysso” of “in mentes abysso” is male, so it does not work for it, neither does “lux” as it would have to be luci or luce.

Obscuritatis lux - the light (nominative singular) of the darkness/unknown/ hidden/obscure (that which is difficult to understand) (genitive singular of obscuritas).

Comment: this has to be the subject of the (sub)clause as it is the only word in nominative.

Se effundat - pour out/forth, spread, shine (se referring to the subject mentioned before (reflexive), effundat is third-person singular of effundo)

In mentēs abysso - in/into (needs accusative or ablative) the minds/conscience/ hearts (nominative, accusative, vocative plural of mens) the abyss (dative or ablative singular of abyssus)

Comment: this seems like wrong grammar as it should be “In mentēs abyssi” (into the minds of the abyss, genitive singular of abyssus).

Conclusion:

I can’t give a straight translation as it seems that this text is either incomplete or the grammar is really wrong. There are other examples of Mihoyo using wrong grammar when making latin sentences, so it would be conceivable. Anyone is welcome to make their own translation using the notes I provided, I have posted my own interpretive version in the KQM discord’s lore channel, but it’s a very liberal and likely wrong one.

Further note:

The sentence on the book is a reference or build on these two known sentences, that have appeared in the game already:

"Lux se effundat in mentes dei"  - light pours forth from the minds of god (should be deorum unless you can use mentes as plural on its own, not sure)

and

 "ex culmine lucis in magno elementorum" - from the pinnacle of light into the great elements, which is also grammatically wrong as it should be elementis

So basically without being to critical of all this we can see this opposing idea of normal "lux" being in the minds of the god(s) probably trying to say that they have a "good" light to them, wisdom etc. and that the in the "mind" of the abyss there is a lux obscuritatis, an obscure "clouded" or "bad" light so to say.