I have been with Fanfiction for many years now and have thoroughly enjoyed that time.
I have decided to create a challenge for anyone to attempt as I really enjoy the Manga of Kingdom, and it is sad that there are only a handful of fanfiction for it. There was a Fanfic called Path of the Conqueror by Wolfblade117 that I really enjoyed; however, it has been almost 3 years since it has been updated so I assume it to be dead (someone please adopt this Fanfic).
I want to go with Wolfblade's idea of having Shin in the GOT universe with his Sword, Wang Yi's Glaive, and Duke Hyou's Shield and being de aged to the age when he fought during Lun hu, so around 16-17. This would allow him to have had the experience of fighting as a General while he is in the GOT universe. I also liked how he would have eventually teamed up with Daenerys as Shin would want a new ruler to serve; and it has to be a great (or potentially great) ruler like the Qin king Ying Zheng for him to serve them. Shin should also introduce Qin armor and army composition(10-5000 man commander) to the GOT universe.
Shin could stars out in Yi Ti(as Yi Ti is the GOT China). In the Yi Ti route, Shin would fighting one of Yi Ti's civil wars and distinguish himself well enough to be rewarded with wealth and the command of troops. And once the civil war is over; somehow shin will have his titles and command stripped from him. Shin would then do what Lian Po did and take his most loyal troops(3-5 thousand) and leave Yi Ti. From there he would wander with his troops from Yi Ti to the Free Cities region where his forces would become famous mercenaries. They would be known as a strong professional army for hire and do very well for themselves. During this time, Shin would be looking for a ruler to serve. He would then someway come to serve Daenerys.
Alternatively someone could just go with what Wolfblade was doing for in his Fanfic and have Shin build up his forces in the Lhazar region and join Daenerys later somehow.