When you’re writing a character inspired by another, it’s all too easy to fall into the trap of writing a copy instead of an homage. Yes, Doc Vandal is very clearly inspired by Doc Savage; he’s an almost superhuman super scientist who lives near the top of the tallest building in New York with a handful of aides and fellow adventurers. The key lies in how you differentiate the new character.
With Doc Vandal, it all started with one simple statement: Doc Savage lives in our world, Doc Vandal doesn’t. Doc Vandal’s world is deliberately more fantastic than Doc Savage’s. Doc Savage has an assistant named Monk Mayfair who is often described as apelike. Doc Vandal’s oldest associate is a silverback gorilla.
On it’s own though, a change like that is little more than filing off the serial numbers and maybe turning up the volume.
Use your inspirations as a foundation. They are the beginning, not the end. Doc Vandal fills the same role in his world as Doc Savage does in his, but the two characters got there in very different ways. What’s most important though is to find your own voice and tell your own stories.
Also, remember it’s been eighty years since the 1930’s. Doc Savage and his team were six white males, and that’s just not something that would work today. Not only does a modern audience expect a more diverse cast, but limiting your characters that way artificially limits your story space. A wider range of characters offers a wider range of story opportunities and any writer would be a fool not to take advantage of that.