S-Rank hunts in Final Fantasy 14 are funny little things. Each S-Rank monster comes with specific spawn conditions, some of which are awfully niche. Want to spawn Armstrong, a monster from Endwalker? Whack on some gear you pick up from a level 46 quest in A Realm Reborn, die in a specific spot and hope he turns up. Spawning Salt and Light requires you to discard items from your inventory 50 times, a painfully tedious process.
With other bizarre spawn conditions including using Blue Mage's self-destruct spell to KO yourself...