Assuming that Li Xinyuan was not boiling with rage as a complementary emotion alongside grief and heartache for Hu Lijing would be a grave, grave understatement.
Just because his demeanour concerning the entire story that Hu Lijing had told him of his life was calm didn't mean that inside Li Xinyuan was not bursting with the murderous desire to kill, slaughter and tear apart those dastardly dragons with his Sui Yue.
He didn't care if he was just a mortal man and those bastards were thousands of years old literal dragons. In his furious state, Li Xinyuan knew only one thing — forget knew — he cared about only one thing.
Dragons were just some freaky arse weirdly big lizards who could fly.
The species that Hu Lijing told him about — Spirit Dragons — just happened to be extra freaky, being able to shapeshift and all.