Many players have discussed the connection the Natural Quad-Elementals have with their Ethereal counterparts. One frequent debate is whether they should be deemed by the Quads' representative Elements, or by all of their Elements. Well, I have a third idea: a correlation based on their designs & sounds.
Quarrister + Whaill: Both have six mouths, with each contributing a part of their harmonic chorus sounds.
Shellbeat + Vhenshun: Both play a collection of sounds consisting partly of idiophones & partly of another family of instruments. Notably, both use a rear-end appendage to strike a round object on their backs.
Entbrat + Pentumbra: Both are tall Monsters with appendages on their heads that directly represent their Element. They also both sing "la".
Deedge + Rhysmuth: Both play electronic sounds using the translucent cubes surrounding them.
Only time will tell if the Poison Quad will be anything like Riff!