Buy the rights to the game characters or modify them a bit?

Question

Copyright

I am writing an application to put it on google play (it will be paid).
From my bitter experience, I know that google play blocks applications that have even the slightest suspicion of someone else's content.
In my application, I need to use pictures and names of creatures from the popular game "Heroes of Might and Magic 3". Where can I buy the rights to creatures?.
I found a bunch of applications on google play that use creatures, although they are slightly redrawn there.
Or you don't need to buy. You just can’t use original pictures, while very similar ones can. That is, you can order from a freelance artist to draw pictures very similar to the original and everything is ok?

Answer 1

It is better to create something based on motives.
That is, you can "order a freelance artist" something in the style of the game .
Nothing more should be done.
Perhaps introduce new characters, it will be something like a fanfic and a parallel universe of this world.