What's the relationship between Royi and Luo Cha?

Xiao Yi and Luo Cha have no direct relationship. Royi is the son of Spark Roman, and Luo Cha is the son of Luo Cha Star. There is no kinship or guidance between them. Royi inherited the power of the flame star representing courage and friendship, and was one of the second generation dragon fighters, while Luo Cha's darkness and nothingness was the source of Luo Cha's power.