Review Detail of DibellaLydia in Death... and me

I dont mind about the grammar as i am not native english speaker, enjoy the story at the first few hundreds chapters, quite unique story as there were dual MC's, and also system. The interaction between them is kinda funny. Yet around chapter 550, suddenly the enemy came and destroy the planet? Seriously? Out of the blue and almost all the characters were killed. Less than 10 survive! Is it real? Feeling so depressed as i thought there would be more character development, more genuine interaction instead of one sided love. Most of them aint making any sense at the later chapter, i think imma stop at 550-ish chapters