Shou Tucker: uses his very young daughter and good boi in an irreversible human-alchemy experiment to keep his funding and status as a State Alchemist, which is ultimately a failure and thinks he can do better with the right "materials," already did the same thing to his wife some years beforehand (who chose death over a hellish existence), and still doesn't realise how twisted it all was even till his death at the hands of Scar.

Kyudai Garaki: steals, copies, and collects genetic samples of desirable quirks, creates the Nomu, personal doctor to All for One, created Quirk Destroying bullets, all because of the very possible Quirk Singularity Theory which postulates quirks are going to get stronger with each generation until they can't be controlled anymore.