(d) https://www.mangago.me/read-manga/doku_wo_kurawaba_sara_made/
not completed though, check cw on the first page of latest chapter
https://www.mangago.me/read-manga/i_can_see_your_stats/
https://www.mangago.me/read-manga/rairairaise/
(technically not regency, but the characters are reincarnated from that era and have scenes)
(c) https://www.mangago.me/read-manga/twinkling_secret_told_us_tonight_is_the_night/
https://www.mangago.me/read-manga/nokemono_domoni_shukufuku_wo/
https://www.mangago.me/read-manga/i_have_to_be_a_great_villain/
lowkey a long ride
To be or not to be!!!
I'm looking for anything BL that has the plot of:
(a) Transmigration into a villain !!
(b) Anything like Erha
(c) Victorian/Regency-esque fantasy worlds (i.e. Winterfield, The Rouge Prince Is Secretly An Omega, etc.)
(d) A+C combined (plus points if it has a system! additionally, it's okay if mc is not transmigrated into a villain!)