#1 The Undertaker

The Undertaker will forever remain as the face of fear in the WWE no one can take that reputation from him by defeating him in a match. WWE tried that with Bray Wyatt at WrestleMania 31, but it was only to give the Undertaker some redemption after his WrestleMania 30 loss against Brock Lesnar.
Bray Wyatt wouldn't gain much momentum even if he beats the Undertaker fair & square in the future as the Deadman has already had the most significant loss of his career against Roman Reigns at WrestleMania 33.
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It would've felt like a passing of the torch moment had Wyatt defeated the Undertaker at WrestleMania 31, but WWE chose to give that moment to Roman Reigns instead. So it wouldn't make much sense if the Fiend decides to target the Deadman once again.
Instead of trying to erase the Undertaker's legacy, Bray Wyatt should choose to build his own. That could be the best way to establish Wyatt as WWE's next face of fear when the Deadman hangs up his boots for good.