"Heritage!" by Paul Kupperberg, Rick Hoberg, and Arne Starr.
Paul Kupperberg was a busy guy, DC mini-series-wise; not too long after finishing up his Phantom Stranger series, he wrote this four-issue Power Girl mini, and he managed to work the Stranger into it!
As Power Girl goes through her paces fighting demons, sorcerers, and super-villains, we see that The Phantom Stranger is watching from afar, looking out for our heroine.
After she deals with various threats, the Stranger makes his presence known:
To be concluded!