UPDATED 8/19 AoS Character Descriptions/Relationships; Major Towns/Facilities

I prepared this for my own use but due to request(s), I tried to polish it up a bit and post it.    It’s a cut-and-paste from several “official” sources (Wiki, tVN and Han Cinema) so spelling/names/etc. are not consistent. If you see major errors, please identify in a kind and courteous manner.  I will try to update weekly. Significant updates/new info is highlighted

The Country Of Daeho

The country of Daeho is built around Lake Gyeongcheondaeho (“Lake G” hereafter).  Lake G was created when the energy of the sky, which rules the wind, clouds and rain, reached the ground and created a huge form of energy.

The capital city is located within Daeho Fortress.  The following are contained within Daeho Fortress:  Cheobugwan; Jinyowon, the Royal Palace and Chwiseonru.

Songrim [Forest?] (also home to Jeongjingak and Sejukwon) can be entered only through a special gate using a Spirit Plaque.

Other locations w/in the country of Daeho include:  Wol Fortress, Seaho Fortress (located in the West Lake Province at the very western tip off Lake G and near the western border of Daeho; Danhyanggok; the village of Sari, and locations where Jang Uk studied, including the village of Yeoengchundang and Gisan.

Main

• Jang Uk - The noble but bad young master of the Daeho Jang's family, a tragic figure with the secret of birth, known by all the people of the country, enters the path of fate through Mu-deok, indwelled with the soul of the best killer in the world, an apprentice of Mu-deok. He  was born on the 1st day of April in Year One of the King Go Sun regime
• Mu-deok (Jin Bu-yeon) - From a blind country woman from Sari village, has the soul of Nak-soo inside her. She becomes Jang Uk’s servant and secret teacher amid a charismatic soul and a weak body imbalance that does not follow her will. She speaks eloquently and reportedly sings well
• Seo Yul - A genius noble of the Seo family, the most prestigious family, he is originally Seo Ho-seong from the western end of Daeho, and has been studying at Jeongjingak since he was young. He is a perfect person with everything, including literary, character, and appearance. He has a love story for a secret girl. His father is General Seo and his aunt is Queen Seo Ha-sun.

Supporting

People around JangUk

• Kim Do-joo - "DeFacto Power" She is the influential figure in charge of the Jang family's large and small affairs, and is neat and strong, but is especially weak in front of Jang Wook. She goes back and forth between friendship and coalition, bickering with Park Jin, the head of Songrim. Originally from Wol Fortress.
• Jang Gang - the head of the Cheonbugwan. Jang Uk's father,
• Do Hwa - Jang Uk’s mother; died in childbirth.  Originally from Wol Fortress.

Songrim - A small city-like living community was formed around the head of Songrim. In Songrim, Jeongjingak, the largest educational institution, and Sejukwon, a medical institution, are located. Songrim was founded by Master Seo Gyeong

• Park Jin - The head of Songrim, the greatest cooperate led by the Park family. He leads Songrim with his explosive charisma and just leadership, but he is struggling because Jang Wook is not at his disposal. With Kim Do-joo, who is the only one who is open-minded, he is maintaining an ambiguous relationship beyond friendship and relationship.
• Park Dang-gu - "Social Butterfly" Park Jin's nephew, heir to Songrim, the largest conglomerate in the country. Even though he is the heir to the top 1% of wealth, he is a super insider who likes to play more than take management classes. 
• Sang-ho - Park Jin's henchman, honest and faithful.
• Cha-beom - The son of a noble family in Jeongjingak
• Gu-hyo - The son of a noble family in Jeongjingak
• Han-yeol - The son of a noble family in Jeongjingak

Sejukwon – the best medical institution in Daeho

• Heo Yeom - The head of Sejukwon, and a drinker with a thin backbone and bright cuteness along with great medical skills. He is a collateral family member of the Seo family. Since the main house of the Seo family is far from the capital city, he takes out the Seo family's representative duties are performed on behalf of the Seo family.
• Heo Yun-ok - Heo Yeom's granddaughter. She's calm and elegant. She has excellent medical skills. Originally from Wol Fortress.
• Sun-i - Heo Yoon-ok's servant, an outspoken character. 
• Councilor Seo Eui-won - Senior Member of Parliament for the Sejuk Circle. A caring and pampered congressman.

Cheonbugwan - a royal agency that examines and records celestial events, The leader of Cheonbugwan is called the Gwanju and it is a hereditary title of the Jang family.

• Jin Mu - Vice-minister of Cheonbugwan, and Jin Ho-kyung's half-brother. He is a teacher who led the performance of the crown prince's art and is close to the royal family. An outspoken character for one's own ambition
• Gil-ju - Jin Moo's subordinate. Follows Jin Moo but is afraid of him. [DEAD] 
• Yeom-su - Jin Moo's subordinate, is quick, witty and greedy
• Cho  Chung he is the caring and affectionate father of the polar Naksu and the Celestial Viceroy Mercury Priest who records and manages the stars of the past.

Jinyowon 200 years ago, a bind female mage (or shaman?) named Jin Seolran founded Jjinyowon.   Inside Jinyowon, which is secretly located in the Jin family, items with mysterious power are stored. These include:  Gwigu, a dog spirit that detects soul-shifters; a binding bracelet with a white magic charm; a magic "Mirror of Longing."

• Jin Ho-Gyeong Jinyowon director, the head of the Jin family, who continues to inherit the maternal line. Behind her powerful charisma, she has affection for her eldest daughter, whom she lost when she was young. A first-time mother. Half-sister to Jin Mu.
• Jin Woo-tak - Jin Ho-kyung's husband, he entered the Jin family as a son-in-law and received Jin's surname. He's looking for his lost daughter. Brother of Shaman Choi
• Jin Cho-yeon - She is Daeho celebrity and the youngest daughter of the Jin family, who looks colorful and dignified, but is a child-like naivete. Ho-Gyeong's and Woo-tak’s daughter.

Royal family

• Go Won - Prince of Daeho, petty and grumpy. He aims for a generous and benevolent monarch, but Moo Deok-I sees humane but nasty side. The son of Go Soon and Ha-Sun.
• Go Soon - The king of Daeho, he became king after his brother who didn’t have a successor. He is always anxious about his position. Go Won’s father.
• Seo Ha-sun - Queen of Daeho. Go Won’s mother.  Paternal aunt to Seo Yul. Ep. 17:  she currently occupies the body of Shaman Choi who was critically burned in a fire 20 years ago. Her brother is General Seo. 
• Shaman Choi - leader of the Danju Group; currently occupying the body of Queen Seo Ha-sun.  Brother of Jin Woo-tak
• Go Seong - The late king. He once made a secret proposal to Janggang before his death.
• Eunuch Oh - The prince's servant.
• Eunuch Kim - The queen's servant. (The "Soul Eater") [DEAD]

Chwiseonru – the highest-class pub in Daehoseong, is the center of social relations among political and business figures and is a hot place frequented by young celebrities.

• Joo Wol - The owner of Chwiseonru
• Ae Hyang – Courtesan (Ep. 2) [DEAD]

Others

• Lee Cheol (Teacher Lee) Master 'Hemp' Lee - His real name is Lee Cheol. He is a mysterious figure who is good at magic, and is called Master ‘Hemp’ Lee because he wears only hemp cloth all year round. He is over 100 years old.  He has a dog named Sapsali 
• Sapsali - Teacher Lee's dog possesses the soul of Gwigu, a soul capable of detecting sorcery, including soul-shifters.  Gwigu was killed by Ho-Gyeong in Ep. 16
• So-i A wandering pickpocket. She was helped by a Mu Deok in Sari Village. She comes to the capital of Daeho in search of Mu-deok and gets caught up in a huge conspiracy.  She was selected by Jin Mu while scamming and is put in the center of a terrible scheme.

Historical

Master Seo Gyeong – the founder of Songrim; he is one of two humans known to have mastered Hwansu.  He was born under the “King’s Star”.  200 years ago, when mages battled over possession of the ice stone, Master Seo Gyeong ended the bloodshed and sealed the stone.

Jin Seol-ran – the founder of Jinyowon.  

Very helpful! Thank you!

 Kathryn_51:

So-yi A wandering pickpocket. She was helped by a Moo Deok in Sarichon. She comes to the capital of Daeho in search of Mu-deok and gets caught up in a huge conspiracy.  She was selected by Jin Moo while scamming and is put in the center of a terrible scheme.

This will be another game-changer to the plot aaaaaaaaahhhhhhhhhh, there are still many ep left too

 Kathryn_51:

Regardless, I'm not sure that So-yi has a very long life at this point. 

Ahhha.... I don't think she does so too considering how ruthless Jin Mu is.

It’s Gwanju, not  Gwangu. And this title is hereditary to Jang fanily, not Kang. Kang was the name of ML's father - Jang Kang. 

Thanks! You might clarify that Lee's Sapsali is Gwigu, which confused me for a while.  (Actually, if I understand correctly,  Sapsali is a Korean dog breed and Gwigu is a ghost Sapsali that possessed the body of the dead Sapsali that Master Lee brought to the Jin vault, but that seems like excessive detail.)

Thank you, @Kathryn_51 for the permission. Thank you, @Cua for your encouragement.

Let's try to find the meaning behind the characters' names. FYI: I don't know how to speak Korean and Chinese (just a bit from watching C-drama), but since Korean also use Chinese characters to write their names, I can find the meaning from the Chinese characters with the help of Google Translate.

*Please also notice that this must have a lot of inaccuracies regarding the translations, so please take this with a grain of salt. If anyone noticed the errors, please quote them, and I will re-edit it again.*

Let's start with our main characters list in MDL:

• Jang Uk: 장욱, 張煜, Zhang Yu: Zhang here is a surname, so usually it doesn't have to have meaning. Yu means brilliant, or glorious. Fitting for a noble young master, and the future's king, ayy?
• Naksu: 낙수, 落壽, Luo Shou: Luo means falling, while Shou means life or longevity. Her codename as an assassin is really cool. This can be implied that whoever she meets will fall from their life, or their heads will fall from their shoulders a.k.a death. That's why she said it's such a beautiful name in ep 1. Ahahaha, our Naksu is so badass, and intimidating. (For her real name, Cho Yeong, please check the next comment under this)
• Mu Deok: 무덕이, 無德, Wu De: Wu here means no, not, or don't. De means moral, or virtue. If Wu is her surname, it would be okay cuz we don't take it into account, but even if it's not the case, still her name together isn't a good one, who tf named their child immoral, lol?!
• Seo Yul: 서율, 徐律, Xu Lu: Xu as a surname, again no need to have meaning. But Xu means slow as a character, while Lu means discipline, restraint, or control. Fitting for Seo Yul cuz he's cold and aloof. He's the perfect young master that is good at everything. But if we take his surname into account too, he's too slow to get the girl ;-;
• Park Jin: 박진, 朴進, Pu Jin: Pu, again, as a surname. Jin means to advance or attack. (The same character of Attack Titan in AoT)
• Maidservant Kim Do Ju: 김도주, 金道主, Jin Daozhu: Jin, again, as a surname. Jin as a character means gold. Dao means path or way. Zhu means master or host. (I think Do Ju is her title instead of her full name.)
  
  Other characters' names:
  
  
• Park Dang-Gu: 박당구, 朴當具, Pu Dangju: Pu, again, as a surname. Dang means appropriate, proper, or right. Ju means tool or equipment.
• Jin Cho-Yeon: 진초연, 陳超妍, Chen Chaoyan: Chen, again, as a surname. As a character, it means to describe or ancient. Chao means to surpass, or exceed. Yan means beautiful. Well, she sure is beautiful.
• Jin Ho-Gyeong: 진호경, 陳湖警, Chen Hujing: Chen, again, as a surname. Hu means lake. Jing means alert, or vigilant. So, that's why she has a suspicious nature.
• Jin Woo-Tak: 진우탁, 陳宇德, Chen Yude: Chen, again, as a surname. Yu means world or universe. De here also means moral, and virtue. Hmm... Same character as Mu Deok's name. Did he leave some trace with her name, so it would be easier to find her again?
• Jin Bu-Yeon: 진부연, 陳复妍, Chen Fuyan: Chen, again, as a surname. Fu means complex, double, or go back. Go back as in return? Ehh... the same as the drama title? XD. Yan means beautiful. (Bu-Yeon, ahh, please reveal yourself and your identity soon, we're dying from waiting for your whereabouts and more backstories.)
• Jang Kang: 장강, 張強, Zhang Qiang: Zhang, again, as a surname. Qiang means powerful. That did explain his status as the strongest mage in Daeho, ayy?
• Do Hwa: 도화, 桃花, Tao Hua: Tao means peach. Hua means flower/blossom. She was also Daeho's prettiest woman. Hmm, such a beautiful name for a tragic character like her.
• Late Emperor Go Seong: 고성, 高城, Gao Cheng: Gao, again, as a surname. As a character, it means high. Cheng means city. 
• Master Heo Yeom: 허염, 許琰, Xu Yan: Xu, again. as a surname. As a character, it means maybe, or perhaps. Yan means gem.
• Young Lady Heo Yun-Ok: 許贇鈺, Xu Yunyu: Xu, again, as a surname. Yun means good appearance. Yu means hard metal, but since 鈺 is the combination of 金 jin (gold) and 玉 yu (jade). We can say that it means treasures.
• Soon-Yi: 순이, 純伊, Chun Yi: Chun means pure, or genuine. Yi means she/he (pronouns), or this, or that.
• Dr. Seo: 徐醫師, Xu Yishi: Xu, again as a surname. Yishi means doctor. (his position) Is he from the same Seo family as Seo Yul?
• Jin Mu: 진무, 陳武, Chen Yu: Chen, again, as a surname. Wu means military or martial.
• Gil-Ju: 길주, 佶柱, Ji Zhi: Ji here, I can't find the meaning of it as a character, but 桔梗 means well sweep. Maybe it's related to his job being Jin Mu's subordinate, and cleaning things behind the scenes for Jin Mu. Zhi means pillar.
• Yeom Soo: 염수, 廉水, Lian Shui: Lian means cheap. Shui means water.
• Crown Prince Go Won: 고원, 高元, Gao Yuan: Gao, again, as a surname. Yuan means first, or primary. Aight, the crown prince always comes first I guess. XD
• Emperor Go Soon: 고순, 高順, Gao Jun: Gao, again, as a surname. Jun means order.
• Empress Seo Ha-Sun: 서하선, 徐荷善, Xu Heshan: Xu, again, as a surname. He means lotus, or carry (burden). Shan means virtuous, or kind.
• Eunuch Oh: 오내관, 五內官, Wu Neiguan: Wu means five. Neiguan is his title.
• Eunuch Kim: 김내관, 金內官, Jin Neiguan: Jin means gold. Neiguan is his title.
• Jo-Wol: 주월, 珠月, Zhu Yue: Zhu means pearl. Yue means moon.
• Courtesan Ae-Hyang: 애향, 愛香, Ai Xiang: Ai means love. Xiang means fragrant.
• Master Lee Chul: 이철선생, 李徹, Li Che: Li, again, as a surname. As a character, it means plum. Che means thorough, or pervade. His title, Hemp Master Lee, 마의 이 선생, 麻衣李先生, Ma Yi Lee Xian Sheng, because he always clothes made from plants, thus hemp.
• Soo-Yi: 소이,索伊, Suo Yi: Suo means to search or demand. Yi means she/he (pronouns), or this, or that.
• Cho Chung: 조충, 趙充, Zhao Chong: Zhao, again, as a surname. As a character, it means to move quickly. Chong means to fill, or full. (At least we got to know Naksu's real surname, Zhao/Cho ayy!!)
• Master Ho-Yeon: 호연법사, 浩然法師, Hao Ran Fa Shi: Hao means grand or geat. Ran means right, or correct. Fa Shi means master (of magic/mage).
• Sang Ho: 상호, 宋浩, Song Hao: Song, again, as a surname. Hao means great or grand.

Place Names:

• Kingdom of Daeho: 대호국, 大湖國, Da Hu Guo: Da means great, or big. Hu means lake. Thus, the Great Lake Kingdom.
• Lake Gyeongcheondaeho: 敬天大湖, Jing Tian Da Hu: Jing means venerate. Tian means Heaven or sky. Da means great or big. Hu means lake.
• Songrim: 송림, 松林, Song Lin: Song means pine. Lin means forest.
• Sejukwon: 세죽원, 細竹院, Xi Zhu Yuan: Xi means fine, Zhu means bamboo. Yuan means courtyard.
• Jinyowon: 진요원, 辰曜院, Chen Yao Yuan: Chen means day or time. Yao means daze, confused, or overwhelm. Yuan means courtyard. That sure does fit this mysterious place full of powerful relics.
• Cheonbugwan: 천부관, 天府館, Tian Fu Guan: Tian means heaven or sky. Fu means resident. Guan means pavilion. This place sure is the resident of the sky/Heaven because they observe and record constellations.
• Chuseonru: 취선루, 取仙樓, Qu Xian Lou: Qu means to choose or pick. Xian means immortal. Lou means tower or building. It usually refers to a restaurant or in this case brothel. It might also mean a place for chosen immortals.
• Danhyanggok: 断响谷, Duan Xiang Gu: Duan means broke. Xiang means sound or ringing. Gu means valley. Together they can mean Broken Sound Valley.

LMAO.... 2:54 AM. I ended up staying up late for AoS again. Changing the colors led to 3:27 AM....lol....

Updated 7/20/22.

All characters identified as "Main" or "Support" Roles have now appeared on the show as of Episode 10.

The only major changes I made were to add Jin Bu-yeon to Mu-deok's character description. and gave Sapsali his own character description.