DUKE OF JUUTEKI/DUKE RONG DI/RONG DI GONG
Japanese Pronunciation: Duke of Juuteki
Chinese Pronunciation: Rong Di Gong(or Lord/Duke Rong Di)
Rong Di(戎翟) is the name of this particular person or a group of people while Gong(公) is his title, the highest possible nobility rank in ancient China, similar to the case of Duke Hyou. For the second word in his name Di, there are multiple pronunciations, including Di, a kind of wild chicken synonymous to the northern barbarian tribes in ancient Chinese culture, and Zhai, a surname. I have no idea which is the correction pronunciation but i will go with Di(reason explained below).
Activities in history
The words Rong Di(戎翟) appeared many times in ShiJi and generally referred to the tribes living outside the borders of ancient China. In ancient China, the tribes living outside the borders of China that were not under the rule of the king of Zhou during the Zhou dynasties were classified into four types based on the location they lived in, either North, South, East or West of the Central Plains(ancient China).
The Northern tribes are called Bei Di(Di of the North) by the Chinese and we refer to them today as the Xiong Nu.
The Southern tribes are Nan Maan(Maan of the South) and they probably refer to the mountain tribes that lived in Yunan province or Indochina today.
The Eastern tribes are called Dong Yi(Yi of the East) and lived North-east of the Central Plains, who will play a major historical role in the late-Tang and Song dynasties more than a millennia later.
Finally the Western tribes are called Xi Rong(Rong of the West) who played a part in the fall of the Western Zhou dynasty. Much of the land were later reclaimed by early Qin kings and became part of Qin territories.
Therefore, Rong Di usually collectively refer to the tribes from the west and north of China then.
The Duke Rong Di in the manga was created based on this entry in Shiji: Annals of Qin Shi Huang:
Lord Chang Xin(Lao Ai) rebelled using the imperial seals, mobilizing county soldiers, guards, calvaries, Lords and Dukes of Rong Di and their men, preparing to start a rebellion in Qi Nian Palace.
As you can see, I translated the phrase referring to Rong Di as “Lords and Dukes of Rong Di”, a group of people instead of one person, which makes more sense as the original text from Shiji had 2 titles(君公) instead of one, clearly referring to a group of people. I am sure Hara Sensei is aware of this and created “Juuteki/Duke Rong Di” as a leader of these “Lords and Dukes of Rong Di” as well as their men.
Indeed, just like what Juuteki said, many of the men from these tribes joined the armies of China, whether Qin or Zhao or whatever, after their tribes were crushed, while some others remained in their homeland.
FAN YU QI/HAN O KI
Japanese Pronunciation: Han O Ki
Chinese Pronunciation: Fan Yu Qi
2.Activities in History
It has been clear now that Fan Yu Qi is not Huan Yi(Kanki) in the manga now.
According to Shiji: Biographies of Assassins(its a long text so i will just do a summary):
居有间，秦将樊於期得罪于秦王，亡之燕，太子受而舍之。鞠武谏曰：“不可。夫以秦王之暴而积怒于燕，足为寒 心，又况闻樊将军之所在乎？是谓‘委肉当饿虎之蹊’也，祸必不振矣！虽有管、晏，不能为之谋也。原太子疾遣 樊将军入匈奴以灭口。请西约三晋，南连齐、楚，北购于单于，其后乃可图也。”太子曰：“太傅之计，旷日弥久 ，心惛然，恐不能须臾。且非独于此也，夫樊将军穷困于天下，归身于丹，丹终不以迫于彊秦而弃所哀怜之交，置 之匈奴，是固丹命卒之时也。原太傅更虑之。”鞠武曰：“夫行危欲求安，造祸而求福，计浅而怨深，连结一人之 后交，不顾国家之大害，此所谓‘资怨而助祸’矣。夫以鸿毛燎于炉炭之上，必无事矣。且以雕鸷之秦，行怨暴之 怒，岂足道哉！燕有田光先生，其为人智深而勇沈，可与谋。”太子曰：“原因太傅而得交于田先生，可乎？”鞠 武曰：“敬诺。”出见田先生，道“太子原图国事于先生也”。田光曰：“敬奉教。”乃造焉。
General Fan Yu Qi offended the king of Qin and fled to Yan. He was accepted by the crown prince of Yan and kept in his residence. Ju Wu thinks that keeping Fan Yu Qi will bring great harm to Yan as he is a highly wanted man of the rampaging Qin. He suggests that the crown prince should offer Fan Yu Qi to the Xiong Nu to prevent Qin from having an excuse to attack Yan. At the same time, he should form an alliance with the other 5 states and the Khan from the north to deal with Qin. The crown prince rejected the idea. Ju Wu suggests that he should then consult Tian Guang of an alternative solution.
久之，荆轲未有行意。秦将王翦破赵，虏赵王，尽收入其地，进兵北略地至燕南界。太子丹恐惧，乃请荆轲曰：“ 秦兵旦暮渡易水，则虽欲长侍足下，岂可得哉！”荆轲曰：“微太子言，臣原谒之。今行而毋信，则秦未可亲也。 夫樊将军，秦王购之金千斤，邑万家。诚得樊将军首与燕督亢之地图，奉献秦王，秦王必说见臣，臣乃得有以报。 ”太子曰：“樊将军穷困来归丹，丹不忍以己之私而伤长者之意，原足下更虑之！”荆轲知太子不忍，乃遂私见樊 於期曰：“秦之遇将军可谓深矣，父母宗族皆为戮没。今闻购将军首金千斤，邑万家，将柰何？”于期仰天太息流 涕曰：“于期每念之，常痛于骨髓，顾计不知所出耳！”荆轲曰：“今有一言可以解燕国之患，报将军之仇者，何 如？”于期乃前曰：“为之柰何？”荆轲曰：“原得将军之首以献秦王，秦王必喜而见臣，臣左手把其袖，右手揕 其匈，然则将军之仇报而燕见陵之愧除矣。将军岂有意乎？”樊於期偏袒搤捥而进曰：“此臣之日夜切齿腐心也， 乃今得闻教！”遂自刭。太子闻之，驰往，伏尸而哭，极哀。既已不可柰何，乃遂盛樊於期首函封之 。
As Wang Jian of Qin crushed Zhao and captured the king of Zhao, closing in on the borders of Yan, the crown prince was worried and consulted Jin Ke for a solution. Jin Ke replied that he lacked something that will earn the trust of the king of Qin if he wants to get near him. He thinks that General Fan Yu Qi’s head as well as a map of Yan’s territories will entice the king of Qin enough for him to allow Jin Ke to get near him. Crown Prince Dan refused as he do not want to betray a friend who seeked refuge under him. Later, Jin Ke met Fan Yu Qi privately as he knew the crown prince would not allow that. He told Fan Yu Qi that there is a way for him to have his revenge on the king of Qin and save Yan at the same time. Jin Ke explained his plan of using his head to get close and kill him with a poison dagger. Upon hearing, Fan Yu Qi cut his own head off and offer it to Jin Ke immediately.
3.Huan Yi≠Fan Yu Qi
Due to the lack of records of Huan Yi after the Battle of Fei and Fan Yu Qi’s mysterious past, many modern scholars theorized that they are the same person. For more information about this, do refer to Huan Yi/Kanki’s post in this thread. Hara Sensei decided to make two different characters for Fan Yu Qi and Huan Yi and in this manga, Fan Yu Qi is the rebel general from the Lao Ai rebellion(Do note that there were no records of Fan Yu Qi participating in the Lao Ai rebellion). Considering the Lao Ai rebellion is doomed to fail, we can be pretty sure that Fan Yu Qi will be wanted by Qin for his crimes in the Lao Ai rebellion in the manga. We can also be sure he will survive the rebellion, somehow escape to Yan and will reappear years later just before the Jin Ke assassination.