Deathsaurus (Unknown Evil)

The "Unknown Evil" (aka Deathsaurus) was one of the nine Fan Vote 2017 nominees. The Power of the Primes fan vote consisted of nine candidates across three categories - Order, Chaos, and Honor. "Unknown Evil" was in the chaos category. He did not win his category's vote (Optimus Primal, the eventual winner, came out in front), but he got enough votes to make it into the second round of voting as a wildcard nominee, although he lost the final vote.

We don't know why Hasbro chose to run with "Unknown Evil" instead of the character's actual name, but we'd imagine it's because Deathsaurus has a distinctly non kid-friendly name and Hasbro has been inconsistent with his English name across his past western releases.