[Original male protagonist + Pokemon + Blue as the love interest + Lorelei as the big sister + crossover setting + slice of life focus + no level system + original worldbuilding]
A stoic young man from the Sevii Islands arrives in the Kanto region, dreaming of becoming a Trainer as strong as his sister.
A chance encounter, an old grudge, and a tale of love and rivalry.
From being unable to stand the sight of each other to entrusting each other with their backs.
Blue (grinning): Team up with me for 200 years.
Ming Lang: Why 200 years?
Blue: Because you can only believe half of what I say.
