Yanyu's deceased husband, a Captain in the Dragon Army. He was posted on the Northern Wall, and he died in a battle against northern barbarians not-very-long pre-game.
After Opening Cages, Wei Han, Yanyu, and Cai Wen went to investigate the events surrounding his death. Before his death, Qin Mingli had expressed to Yanyu that he did not agree with some of methods of Commander Lo Ping; and since he wasn't the sort to say such things lightly, Yanyu thought this significant. A recent Connections reading had established that Lo Ping did not arrange Qin Mingli's death.
Cai Wen's survey of the civilians in the area found that Qin Mingli was well-liked and respected. Not well-liked in the gregarious sense; well-liked because he was decent, and not looking for payoffs.
All accounts agree that a barbarian force assaulted the Wall one night, while a raiding force crossed the wall at another location. The assault may or may not have been co-ordinated with the raid, but it absorbed enough Dragon Army attention that the raiding force got pretty far into Imperial territory. Captain Qin's unit, starting pretty far to the east, was the first to catch up with the raiders, south and west of Daizhou. Many accounts say he was outnumbered, but that may be a fiction to avoid admitting the skill and toughness of the raiding force. After Captain Qin and many of his men were killed, more reinforcements showed up and wiped out the barbarians. Any loot they may have been carrying was "taken charge of" by Lo Ping.
There was a lot of digging at the battle site. Many people think this was an attempt at emergency fortifications by the barbarians, but they aren't fortifications; the barbarians were digging for something (though we can't rule out that they might have been trying to bury something), and it doesn't look (to Wei Han) like they finished what they were doing. If they were looking for something, it wasn't a major excavation; it was fairly focused. It doesn't look like there has been any other digging in the area in recent times; the ground is thick with gopher warrens and the like, that haven't been disturbed recently.
Cai Wen thought that the surrounding terrain felt like it was right on the border between what he thought of as the Hon'eth Arcade, and what he thought of as "Near the Wall". Yanyu concluded that the battle site is just to the south of the (fairly wide) chi border between the Empire and the North.
Another trip back to the site for further investigation didn't reveal anything.
Cai Wen later (after Odds and Ends) asked Chiyo for help in figuring out what was dug up. She got some information, and introduced Cai Wen to one of the guys who helped transport the loot. The description: A life-sized jade statue of a man in armor