The Pillars are a structure in the Blaseball cosmology which may or may not be related to the Ballpark of the same name.
The Pillars have been mentioned several times in various contexts.
In the Season 12 Elections, following the passage of Based Evolution:
FROM NURSERY TO VAULT PILLARS QUAKE ACCRETION FIRST STEPS ROUNDING FIRST
In the Season 15 Elections, by Lōotcrates:
"From the Vault Gifts forged in Stars. Tools of the New Age." "The Enquiry begins again." "Memories flood. Overtake the Bridge Erode the Pillars." "A witness wades." "Witnesses shape the Current Carrying sediment Etching Names in keepsakes." "Crafting Legends."
In the Chapter "An Ascension" from the Root volume in The Library:
"A Raise"