User blog comment:The Woolly Howl/Rise of Berk Titans/@comment-25046825-20150710164226/@comment-26219548-20150712091730

Perhaps. This may explain why alphas are rarer and more powerful.

Being an alpha may also be because of inheritance, I guess. The Red Death/Green Death, Bewilderbeast or Foreverwing are titans because of their species. I think that they are still alphas even when not in the titan wing stage. That's just my speculation, though.