The Tower of Knowledge has a row of numbered gargoyle statues, and nothing in the game says which ones to light. Three separate players give the same answer.
Which gargoyles do you light?
Light gargoyles #3 and #7 only.
- Where: Digitol's 100% guide places the puzzle on the first balcony on the left, above the large Manticore floor. Both gargoyles you need are on that same balcony. The Chinese 100% guide by Sdaknight also puts it on the 3rd-floor balcony.
- How: use the Azure Torch's flame on each statue. You get the Torch from the gargoyle in front of the Tower entrance; see the Tower of Knowledge guide.
- Confirmation: on Reddit, DignityThief80 lit #3 and #7 and asked why nothing happened. Fierumbras replied that they had done the same thing and the door it opens is elsewhere (see the next section).
Why didn't the door open?
This is the part that trips people up. The gate right next to the gargoyles stays shut. Fierumbras explains that the door you have opened is back inside the main body of the building, not the gate near the gargoyles.
Digitol describes it as the nearby sealed door "that requires two gems", which the two lit gargoyles count as. Past it is a corridor of Poltergeists and Pus Bags and a window. Digitol continues: open the window, land on the large platform to the left and pull the lever there. According to Digitol, that lever opens a secret door near the trap-door path with the Wind Rapier inside. SquidRadio's walkthrough found the Wind Rapier earlier, in a chest in a room off the hall with the book The End of Epha, so the exact spot is to be confirmed.
Sdaknight's guide adds a food pickup: after solving the puzzle, go through the door, jump out of the window, turn right 180° and fly into the other window for Roasted Poultry and a Meal Ticket.
What happens if you light the wrong gargoyle?
Nothing is lost, but enemies appear. Most players report that a wrong statue spawns a group of Book Bugs; SquidRadio's walkthrough says the statue itself comes to life as an enemy. Players actually use this on purpose: horrid little goblin on Steam calls it the best spot they found to level weapons, with five gargoyles each spawning about five or six Book Bugs, right next to a save point once that shortcut is open. Kripsu uses the same trick in a weapon-evolution video. Unovalocity adds that the gargoyles resist Slash, so bring something else for them.
More leveling tips are on the weapon evolution page.
What other gargoyle secrets are there?
The Tower has more gargoyle tricks than the numbered puzzle:
- The Azure Torch itself sits in the hands of the gargoyle statue in front of the Tower's main door (Digitol, Sdaknight).
- The beacons that open the Tower are lit by shooting the Azure Torch into gargoyle mouths (Digitol). See the walkthrough.
- Secret door at the Tower entrance: valiant43e on Steam found a hidden door just inside the front entrance that would not open. LSB777 answered: shoot the Azure Torch's fireball at the open-mouthed gargoyles high up in that same corridor. Sdaknight's guide describes the same thing and says it leads to Broiled Meat and a Meal Ticket.
- The Docile Gargoyle: on the Tower's exterior near the wing portal, one gargoyle wears a monocle and has books in front of it. Hit it a few times and it turns hostile (PovKetz's bestiary guide). Sdaknight notes it drops a monocle treasure, and it counts toward the bestiary.