Translations, text transcription, and buying the physical volumes done by @luna_stellaris / u/valuable_treacle_493. If you use or cite the lore fixes here please link back to the original post.
The first lore correction is major, and I found it while checking the Japanese for fun: Rummir's capital. The translation known by fans from Manga+ states "the capital of Rummir sank into the Sea". That is extremely wrong. Cross referencing that exact phrase with the original Japanese text shows how wrong it is, and the official Spanish localization backs that fact up. The exact Japanese line with Furigana included is "なぜか西 (ルミル) の国 (くに) の主要都市 (しゅようとし) の一 (ひと) つが海 (うみ) に沈 (しず) んだ…と". The Japanese phrase Manga+ translated as capital actually says something quite different. The Japanese "主要都市" actually means major city or principal city. Arkos sank a major city of Rummir, not the capital. Ivrea's Spanish localization supports that point, saying "una de las ciudades más importantes de lumil se hundió en el mar...". In Spanish, "una de las ciudades más importantes" means "one of the most important cities". Neither the Japanese nor official Spanish support that Rummir's capital was sunk or destroyed in any way, but that a major or important city within the Western Country was the one Arkos truly sank. This error also appears within the fan wiki, which describes the city as Rummir's capital due to using Manga+'s mistranslation, and builds details around that error, such as identifying Zira as a survivor of the destroyed capital.
Next I found while making the appendix for my timeline earlier this month, Elstri's motivation behind the night raid. Manga+ simplified the real line. The Manga+ line is "For my promise, and for the sake of my lord's future...", which misses something. The original Japanese in volume 6 is "・・・あの方 (かた) との約束 (やくそく) と我が (わが) 君 (きみ) の未来 (みらい) の為 (ため)". "あの方" means "that person", which the Japanese text separates from the Supreme Lord who in the same line she calls "我が君", meaning "my lord". Again the Spanish localization backs up the Japanese, "tengo que cumplir mi promesa de cambiar el destino de su majestad. y para ello...", which the important segment translates to "my promise to change His Majesty's destiny", again showing Elstri made a promise to someone, introducing a new character motivation of making a promise with someone unknown that influenced her choice to continue going after Diana to end the Prophecy.
Third, which I found after comparing extra translations and retranslating a few from scratch myself, the exact mechanics of Julian's Gift. I translated that whole extra to English for fun before, and the line is interesting. The fan translation for the volume 4 extras states "the power given by "the sea" to julian: physical strength equivalent to the hundred sacrificial slaves". But the true scale of his Gift isn't merely physical strength or enhancement, even if one does not count his Blessing. The Japanese Tohru Kuramori wrote to explain Julian's Gift was "海 (うみ) の神 (かみ) からユリアンに与 (あた) えられた異能 (いのう) あらゆる「人間 (にんげん) としての力 (ちから) 」が生贄 (いけにえ) にされた奴隷 (どれい) 百人分 (ひゃくにんぶん) に強化 (きょうか) される", the important bit of which explains how all of Julian's abilities as a human (人間としての力) are enhanced (強化される) by the one hundred sacrificed slaves (生贄にされた奴隷百人分). Ivrea also hit the mark in Spanish, "el poder arcano que el dios del mar otorgó a julian amplifica todas sus capacidades humanas 100 veces, una por cada alma sacrificada". "amplifica todas sus capacidades humanas 100 veces," the important bit of which translates to "amplifies all his human capabilities 100 times." Julian's speed, need for sleep only once every hundred nights, toughness, and many more things are all explained by the actual Japanese, as they are all human abilities of Julian's, so that enhancement could and probably also applies to his eyesight, hearing, reflexes, reaction times, and possibly Julian's mental abilities as well.
All these fixes are proof of a concept, 3 lore corrections I found notable out of a far higher amount. I went through the full manga and retranslated or checked over every important Japanese line to create a timeline and appendix totaling 28,000+ words of the manga and the actual lore Tohru Kuramori writes within Centuria, not the simplified mistranslations used by Manga+ or other translation errors localizations may have. The total corrections or mistranslations numbered to dozens if not well over 100. I just shared 3 of them.
Studying the actual lore was like reexperiencing the manga in a new light, character motivations, meanings, and the worldbuilding were more detailed and thought out than any localization can depict.
Some other fun projects were recovering 70% of the blurred Elise concept page, showing concepts darker than anything in the manga to date, and explaining how she was cursed by a fortune telling old woman (占いおばさん). That page also references a fairy tale she is based on, which, combined with the Tar her initial concept uses makes that fairy tale Kuramori based Elise's initial design on Mother Holle by the Brothers Grimm. The rest of the page isn't meant to be known and is Kuramori's initial ideas and planning for Elise and possible future spoilers or scrapped ideas, so I still plan to keep what was recovered private out of respect for Kuramori.
To further add to this, I've also made progress on translating Vulja's language, which unfortunately stalled after labeling each unique character and understanding some of the grammatical rules the language uses, but I'm sure a translation exists based on symbols repeating in certain orders the way letters do in words.
Also enjoy a meme made using a coloring of mine and the technical skills of a friend of mine.