Death Parade's darkness and morality are well-known. Each episode features games to judge the dead. The anime questions human nature.
Death Parade's plot and ethics were mysterious. Because something is "missing," this anime wouldn't be as popular today. The anime's information feels incomplete, which leaves some dissatisfied. Monotone characters in a booming isekai trend would push this anime from the front lines.
Disclaimer: The photo belongs to its rightful owner.