It was set in old timey Japan but not like old old days. The mc is adopted by an old man and another younger boy is later brought in. It has hint of shady very gross stuff regarding the adoption. Mc worries about being replaced soon and he like planned to run away with a boy from his school. There was also a mystery of the mc and little boy being bird like creatures. I cannot for the life of me remained the title TT-TT please help
Why was the reincarnation added when it's such an unused part of the entire thing? This could have just been a standalone story without it and it would have been better, seeing actual children trying to rationalize and survive the situation. Nothing was done with the previous knowledge, there was no true attempt to actually fight the situation using said knowledge