A date

The key to Serpentara.

At first glance, it appears to be nothing more than a simple silver key, its surface engraved with the image of a serpent coiling around it. But under my unique sight, it reveals something far more complex: hundreds of Arcanum lines, intricately inscribed in Serpent Tongue, forming a cryptic network of magic.

Every door in Ariella's mansion is crafted from Ironbark, a rare, nearly indestructible wood that can resist even the most powerful of spells. A dimensional gate spell should pose no challenge. With that thought in mind, I insert the key into the lock of my room's door.

As the key nears the lock, the serpent on its shaft begins to shift, its coils twisting and reforming.

"Oh, fascinating," I murmur to myself. "So, Omni-fitting is one of the enchantments."

In other words, it's a key that can fit any lock, regardless of its design.

Click.

As expected, it fits perfectly.