Great illustrative work!
It's hard to say which is better. The top 2 have stronger contrast in values, but there's something I like more about the bottom 2. I think the softer values and lighter colours in the bottom 2 helps the champion and her leviathans blend more with the environment, as if the mist from the seawater is causing the softer contrast.
In short, either 3 or 4 from me personally. Nice work. You've got an eye for detail. 