How many eroge/H anime were there were the sex was used as a means of powering up and or fighting?
Escalayer had her Doki Doki Dynamo that needed her to be aroused to be charged and the Djibril series I think used a similar plot set up minus the cybernetic parts.
I recall the classic La Blue Girl series used sex as a means of "fighting", even after all these years I still get a laugh out of that.