"High School DxD but we replace the chess mechanic with Yugioh Cards!" That's what the boardroom came up with and they name it Maou Gakuen no Hangyakusha. Both have many similarities -MC with a special ability -Harem of girls that can use abilities to back him up -Plenty of fanservice and comedy to motor(boat) the plot -Some good drama/flashbacks that develops side characters That being said, just because it's diet High School DxD doesn't mean it's better. There are clear signs of a rushed ending to avoid axe-kun (the author has had other works cancelled or paused in the past) despite the great art. If it got another 50+chapters to layout the rest of the story and characters it could have been much better.

If you want to breeze through another fanservice/guilty pleasure read in your free time then check it out, but they're better one's out there IMO