I don't get it myself. I recognize it as one that's been used before, but I'm not familiar with what it is for.
Ah, okay. My avatar's Tomo Takino (Azumanga Daioh), and physically speaking she's the basis for Callista's appearance. As for the Castlevania reference...
Jojo ruined music for me, now when I hear artists or songs I think of the jojo stand or character instead of the song. Most notably with Killer queen and his ability bites the dust. Oh yea and Robert EO Speedwagon.
I think it's cool to such music references, in particular awesome music, but it has the downside of possibly moving attention away from the music and more to Jojo. At the same time though, people might come across the music for the first time and enjoy it, like Yes' Roundabout as the outro music.
I don't knowingly listen to any of that stuff.... then again unless it's an album I've purchased or any artist youtube channel I never know what I'm listening too.