The title Kaerutope fuses "kaeru" (frog) with "biotope," creating a neologism meaning "frog habitat"—a characteristically poetic gesture from an artist whose veganism and animal rights advocacy have profoundly shaped his work since 2003. For Masami Akita, sound itself becomes ecosystem, a living environment where listeners immerse themselves in complex, interacting sonic organisms.

This album showcases Merzbow at his most texturally adventurous. Bit-crushed noise collides with sampled instrumental fragments in a manner reminiscent of Hyakki Echo, yet the result feels distinctly organic—like observing a sonic ecosystem in constant flux. The four "Frog" variations (V1 through V5, skipping V4 which appears on companion album Indigo Dada) explore different aspects of the amphibian metaphor: sometimes dense and murky like pond water, sometimes sharp and sudden like a frog's leap, always teeming with microscopic detail.

At moments, the dense noise resembles a muddy torrent flowing through an imagined landscape, quietly subverting expectations of what harsh noise can evoke. Akita proves once again that his work transcends genre limitations, offering immersive experiences rather than mere assaults. The album rewards repeated listening, revealing new details with each encounter—much like returning to a natural habitat and noticing species previously overlooked.