His name has two meanings. One of them is Sōlis, the genitive of Sōl (Sun); so one possible reading would be Yue Hu as Sun's, of the Sun, Solar. The other is Sōlīs, ablative plural of sōlus (lonely, loneliness); as if Solis was born by the loneliness of Yue Hue and Fei Liai.
I'm almost sure the...