The Goddess of Darkness & the Temple assists Jules in his quest by allowing him to store some of his equipment, including his Companion Gwell, partially in the Otherworld. Jules wears the same vintage, 50 Liter backpack for this effect, the same he wore when he discovered the Seal of Nephthys. This backpack is now weightless, regardless of contents, & can carry an astonishing 250 Liters. However, it can only be opened in Shadows or Darkness. Attempts to open it in full light reveal an empty pack.
You possess a Backpack that holds 12x times what it should, given its dimensions. There is no cost to use your container. Objects stored inside are weightless.
Living things can be stored in your Backpack. But they will have access to anything else that is inside and may attempt to break free, damaging or destroying the Backpack in the process.
If your Backpack is destroyed, things inside may get out, and it will cease to function, but it can be repaired.