Reincarnated as a beneficial bacteria (MHA)

Spark is one heck of a puppy only 1 and a half years old but when his owner take him to the vet it seems' he's dying of a very rare disease and for his last days on earth Spark will love his owner to the last second but when he dies he sees his owner eye filled with tears he wishes his owner didn't cry Spark wish he can be with his owner in his next life

Disclaimer/Spoiler
(owner was originally a girl and being reincarnated with Spark sort of but Spark is the main character and the girl will be reincarnated as Isuku)

Maybe 2 chapters a week
oh and the picture is supposed to be bacteria