Read the whole thing and I like your ideas for the arena and I somewhat understand what you are looking for here.
The three background which matches the arena will be the toughest to create haha. On top of that sometimes the arena theme changes based on the type so it's becomes a bit more tricky here to match it with the said backgrounds. As for the border we can just blend it with the arena as it moves towards the center.
I have some questions.
What kind of view are you looking here? Like top view, side view drawing etc
Coloured or lineart?
Good questions, basically it'd just need to "blend" in at the edges of the arena and center so it wouldn't look too alien to each other.
Like say the ocean side which has some puddles and water and stuff would closer to the center become mud/ground to then fade into the ground/grass of the other half. While they both on the outside start to fade into the "background".
For the main image we'd wanna use on the website, etc, we'd want it say the camera not too high from the ground behind one of the healers with focus on the arena, healer and creature on the other side and the background.
A little like this random example from google but potentially closer and smaller arena compared to the one here so the creatures and healers are clearly visible:
We'd be okay with the background being colored only while the characters include lineart.
Upvoting your comment to the top for this reply since it's too late for me to edit the post right now.
Even if I placed the characters in this arena they will be small and slightly blurry unless they are very close don't you think? When you see pictures like this the idea is to show the picture as a whole. I can try drawing in 3k and see if the results are good. Are you looking for backgrounds drawn in landscape mode like this?
I forgot to ask the deadline for this if any?
Another example:
Looks like this one will be much more useful since it's a bit more zoomed in. In this type of view the healers should be placed left and right and a split in the middle shows the are from different elements. Are you okay with the backgrounds drawn in this angle?
Yeah something like this example would probably be perfect, just to get a shot of the different elements of the arena and the background along with a lively battle occurring in the center.
Left and right on the healers sounds great too!
Need sleep now, will check back tomorrow morning
Alright! I'll see what I can do.
Good night 💤