Shikamaru's Pokemon Adventure
1.- shikamaru dies and is reborn as Ash bother, must be twins can be identical or fraternal
2.- must specify in prologue around how strong he is and knowledge of shinobi skills
3.- Shikamaru keeps his memory and chakra levels but has to retrain his control, ect
4.- Shikamaru travel separately from ash, so he would be one of the ones that were early so his starter must be either bulbazor or charmander, gary has squirttle and ash pikachu
5.- he can be pokemon handler were he can take all of his pokemon with him and participate in both contest and gyms
6.- he still is a lazy genius but he like being a pokemon trainer best because he doesn't have to worry about someone trying to kill him because of a bounty and it less troublesome
7.- can be single pairing or harem as long as it is not misty she is Ash's