 If you liked
Houseki no Kuni
|
 ...then you might like
NieR:Automata
|
Both series depict a never-ending war between two different lifeforms with ties to humanity over the course of hundreds if not thousands of years. The implications of these conflicts change with significant twists later in the story.
The protagonists also both undergo severe mental deterioration after a traumatic event causes them to change forever.
Both series have a strong focus on themes of existentialism and purpose in a world devoid of it. If you love Nier you'll also love Land of the Lustrous (and vice versa).