Earth? Not a place he's heard of, but that hardly means anything here with so many different people from various worlds. Even she is not something he's ever seen before. Clearly not human, but she's not acting any different than the regular people he's seen on Gaia.

He'll not-so-gently drop the creature as it no longer holds his interest. Right now she has his focus since she's something new and despite his general loss of humanity there's still a lingering hint of curiosity hidden somewhere.

Which is why Sephiroth will let her go through the whole song before asking, "Is Earth where you're from?"

His Mother is also from the stars and part of him wonders how many worlds she visited and what other places were like.