If I buy a Defender Series Otterbox from Amazon, will it void the guarantee/warranty?

I've heard that if Otterbox doesn't defend your iPhone against what it says it will, it will replace your iPhone. If I buy one off of Amazon, will it void that guarantee/warranty?

They won't replace an iPhone only the case as people with broken iPhones can buy it then get a new iPhone. And no buying it off amazon won't void any warranty