Indeed, I believe its use originated with Metis Highland, founder of Triunism, and Hireshy has kept using from his days as a Triunist.
It's a Dark Tower Trilogy reference that Metis made into a Triunist thing, and then Hireshmont started using it, and kept it post-conversion. He also occasionally uses "humbly". If he ever uses that finish to a letter, its an acknowledgment of having bee soundly trounced in some contest. It's his way of conceding.
Onamont uses nationalist slogans.
Cyrilos uses a Way of the Warrior Saints proverb.
Alecsander uses kinda tongue-in-cheek Astroist slogans.