Lilia’s unique magic Far Cry Cradle (hidden meaning: Until the Distant Cradle) enables him to see memories of the distant past. After learning it he explains to Malleus, “This spell allows me to replay a fragment of the memories stored in objects…though it only ever shows me utterly trivial things when I cast it. I suppose I haven’t mastered its use enough to filter out all but the important bits.”
We see Lilia discover his unique magic while traveling in a foreign land that it took him years to reach. Desperately seeking out a way to save the unborn Malleus’ life, he says, “If there aren’t any fae or bugs, then I’ll take a piece of castle furnishings. Even a bit of tattered carpet…Please, I’ll take anyone… Anything… Just tell me something!”
The spell then shows him memories of the objects in the place that he has found.
While the location of the land is never said aloud the background is identical to scenery seen in the Spectral Realm, and we have confirmation from Silver that Lilia has visited the Spectral Realm in the past.
According to Silver, Lilia told him that he came to the border between life and death and immediately went right back. But Lilia is known to be less than truthful sometimes (ref: Lilia’s Secrets), making it not impossible that Lilia went as far as the Spectral Realm in search of a way to save Malleus.
Lilia seems to combine his unique magic with Malleus’ magic in Book 7 to “conjure memories of the throne room (of Castle Wildrose) from bygone days” that others can see as well. Grim asks if the projections of fae royal guardsmen and Silver Owls are ghosts and Silver says no. Lilia also conjures apparitions of Silver’s birth parents, and Malleus’ mother.
When Meleanor seems to react to them Lilia asks, “You ARE a memory of this castle conjured by my signature spell, right? You’re not a ghost, are you?!”
Twisted Wonderland Reference Note 