>>264144112Eiyuu - Someone making a new for themselves on the battlefield or otherwise, basically a "war hero" but also refers to figures of legends. It used for the "heroic spirits" in the Fate/ franchise.
Yuusha - The nemesis of the Maou (demon lord). Basically a monster slayer and the leader of an elite team that is out to hunt down the demon lord. Sometimes the only one who can even hurt the demon lord or even destined to oppose him, has a "the chosen one" kind of vibe going in many cases.
Hiirou - Capeshit, but in some cases also just used interchangeably with Eiyuu, in rare cases with Yuusha.
Seigei no Mikata - "Ally of Justice", can also refer to capeshit if the author doesn't like loanwords, sometimes it also has a very abstract meaning such as when Shirou or Kiritsugu from Fate/ use it.
But none of those are absolute. Sometimes the author just comes up with completely out-of-the-left-field definitions for these.