This is a long time project I've been working on ever since Legendary announced their plans for a sequel to Godzilla. I've been working on this Legendary version of King Ghidorah for years! And I'm still not done! As time has gone on and I've practiced more anatomy the design has changed. These are the concepts I've made so far, and hopefully I'll settle on a finallized design soon.
My idea with this incarnation of King Ghidorah was basically going by the lore of Legendary Godzilla; a creature that had adapted to feed on radiation. So King Ghidorah feeds on radiation, but by absorbing radiation from the sun using its massive wings as solar panels. I'm still working on the concept sketches for its body, so that's why these sketches are just of the head.
v1 & v2 - no reference, just winging it. But drew inspiration from spitting cobras
v3 - based on spitting cobras and electric eel, first time I used actual references.
v4 - just fine tuning the proportions
v5 - skull and muscle study. King Ghidorah always uses electrical attacks so I had figured early on in these concepts how it may do so, but this is the first time I ever drew the idea out. My idea was that it uses specialized muscles to produce electricity (like the electric eeel does, hence the inspiration), and it also utilizes venom. But its venom is very conductive, so it can spray its venom and by utilising its electro-muscles at the same time, can "breath" bolts of lightning. The reason it's fangs are located far back was so it looks more like it's breathing lightning instead of just spitting.
v6 & v7 - experimenting with making it look more snake-like, and removing the spines that would've formed a frill of sorts
v8 - most recent version, removed some horns and added spines on the plates. at this point it is more snake-like rather than being a mix of snake and electric eel. Still tweaking its design so this isn't the final version
King Ghidorah (c) Toho