In the Omori game you can obtain a number of keys. These keyboard keys are labeled with a capital letter. The letter keys start with A all the way to Z. You can find the I key here.
Omori Location Key J
You can find the Omori J Key in the pink cage in Sweethearts Castle.
Only Omori can collect the J Key. In case Kel, Hero or Aubrey are leading the party the J letter key will be semi-transparent. A semi-transparent key can not be collected.
Looking for Key K. Find the Omori Key K.
You can find all Omori key locations here.