Are you at all familiar with Boito's opera Mefistofele? I personally find his Mephistopheles more interesting than Gounod's--I especially love his arias "Son lo Spirito" and "Ave Signor". (Boito is more well known as a librettist for Verdi, but he wrote this opera too!)

Here's Samuel Ramey singing "Son lo Spirito," and a translation:
https://youtu.be/-PZS_L6mH1M
https://opera-cat.dreamwidth.org/4925.html