Trust me, you're gonna want a second Fortoytops instead of a Graviton Earth Dragon if you have the choice. The GED's nuke attack won't even take off half the life from the Taurus Demons, and it's extra HP and ATK won't be nearly as helpful as Fortoytops' orb-to-hearts skill. When the Wind Mech got low on life, it performed multiple special attacks on me. I had to utitlize all 3 orb-to-heart changers plus my Echidna to stay alive, before it reverted back to normal attacks. I barely survived at several points with my dual Fortoytops, max-skill Siren, and Echidna.
Yeah, Echidna was my last resort safety net. I didn't even use her skill every time it was charged. I saved it for when I was staring at certain death, or if I ran into multiple Taurus Demons and didn't have my nuke charged then I'd activate her skill before they had a chance to bind me. She really is super useful, not to mention strong against Wood monsters.