Why did luna predict that Nie Gai would be killed before dawn?

Nie Gai killed Jing Ke. I don't know if it's a historical fact. That's what the movie said. You may not have seen the ending of the second movie. You'll know after watching the third film. It was Mo Qijia who stabbed Nie Gai at the end of the movie, but his uncle didn't die. In the original Jing Ke Rumors, it seems that Nie Gai didn't kill Jing Ke. The historical fact is that Nie Gai and Jing Ke met once and broke up because of their different views on kendo. Later, Jing Ke wanted to help him stab Qin, but he couldn't find it, so he let Qin Wuyang go, so it was very tangled.