The Shinsengumi are a genuine part of history with many modern pop culture adaptations, tropes intake.
Souji Okita will almost always be tragic and tubercular -- if you Google his name, his historical Wikipedia profile will appear alongside art of his Hakuoki incarnation.
Last year Idea Factory opened an International publishing arm in the United States and many otome fans were hopeful that this would mean an opening up of Otomate titles in English , but so far they have only released further rehashes of their Hyperdimension Neptunia games and some RPGs. Hakuoki is available in English on a wide range of platforms.
You can buy it on PSP, download it to PS Vita or TV via PSN, buy or download it for Nintendo 3DS, or buy/download it to the PS3 (and even stream it via Playstation Now).
You play as Chizuru, who disguises herself as a man to travel to the capital of Kyoto in search of her missing father.