It’s a basically a layer of flex tube and clips for the bottom row, then octagon 2x2s for the next layer up, then one more bit of flex tube and some other random attachment points to fill in the gaps.
The cloud is brilliant and unique. This moc has the most inspired use of voltix’s thunderbolts I have seen in a while. If I had any criticism, it would be that the feet of the demon are too small and that the micro village looks rather static for experiencing a storm. Maybe throwing in a tornado or making the trees seem like they’re being blown by gusts of wind would improve this moc some more.