Compulsion King by Neil Bimbeau is more story focused than erotica and it is mind control, but the harem elements would likely have increased if the series had continued.
Compulsion King: The Supervillain's Harem https://www.amazon.com/dp/B08SF99N91/ref=cm_sw_r_apan_BM9Q70A9SD1QEAYVTCGK
Neil Bimbeau, Compulsion King: The Supervillain's Harem
Description
When I started to develop superpowers, I thought I'd hit the jackpot. Power, respect, women: the Supers have them all. My life was finally going to change.
Then I was branded a villain, betrayed by those closest to me, and tossed into a 're-education facility' to be tortured.
Now I'm free - with a gorgeous, completely insane Super by my side who thinks I'm her King. Together we'll get revenge on all those who have wronged us - and show them what real evil looks like.
You wanted a bad guy? You got one.
Warning: This book contains villainy, vice and unconventional relationships. You know what to expect.
NOTE: Portions of this book appeared in 2017 as the "Alpha Addiction" serial. Compulsion King is a radically expanded full-length novel based loosely on that serialized story.