Excellent question. It’s an oath, anonymous. Those who identify as Johtonian (that is, a member of the religion, not simply someone from Johto) consider oaths such as swearing on Ho-oh or Lugia’s wings—whichever of the two you place at the center of your beliefs—to be equivalent to, say, “as God as my witness” or similar statements the more human-centric followings would make. In other words, it’s perhaps the most serious oath one could make, reserved for promises a person intends on keeping or die trying. Personally, while I do believe that Ho-oh exists, that the story of the Tower is true, that one day, Ho-oh will return to Johto, and that after we die, our souls may be reincarnated, I don’t consider myself a religious fanatic but rather an agnostic open to all possibilities. Still, as much as I don’t believe swearing on Ho-oh’s wings would actually result in my burning should I fail to fulfill my promise (as the story goes), I do like how it adds a certain dramatic flair to vows I actually do intend on at least trying my hardest to keep.

Incidentally, for those who might have wondered about the other Johtonian phrase I’m rather fond of, “blazes” is similar. It’s short for “oh Ho-oh’s blazes” or simply “Ho-oh’s blazes,” which is either an expression of shock or exasperation, depending on context. That one, I admit, is more of a force of habit—not only for myself but many Johtonians as well. The phrase originally began as a sort of prayer, invocation of Ho-oh’s protection (by asking for its sacred flames, rather than Ho-oh itself), plea for purification (by asking Ho-oh and its sacred flames to show you mercy for your sins), or some combination of all three, and it disseminated into our regional vernacular over time, to the point where even the nonreligious say it. There is even a popular rumor that says you can tell whether or not someone was from certain parts of Johto if you surprise them, and they say this. (The truth: No.)

There is also “Ho-oh burn you” or “Lugia take you,” which are both expressions of anger that you say to sworn enemies, but I avoid using either. For one thing, I find such intense negativity towards another living being rather counterproductive, not to mention counter to my own personal beliefs. For another, it’s a bit of a taboo to ask either legendary to do anything serious on your behalf, even if it is simply an expression.

In case you’re wondering, there are no expressions for the legendary beasts, as they’re often seen as messengers of Ho-oh and thus don’t offer blessings or curses themselves. Celebi, on the other hand, gets “Celebi’s blessings,” which is said on holidays as a greeting … or after one sneezes. The latter has to do with the highly outdated belief that your soul escapes when you sneeze, so asking for Celebi’s blessings is meant to stop time and allow you to catch your soul so you don’t die.