Ange had no idea that Little Sapling and Little Ghost were linked in any way. Little Ghost had previously slipped into the Divine Aspect of Light and had not responded since; he didn't know when it woke up.
Little Sapling possessed the ability to transfer consciousness across planes, likely after planting its avatar in Iron Sand City. But to transfer smoothly, it seemed that it would need to wait until the world channel was fully open.
The Holy Kingdom harbored several War Giant Trees. Little Sapling could grow its avatars by borrowing them, entering the core of the Holy Kingdom; that must have been how it made contact.
As consciousness returned to its main body on Ange's shoulder, Little Sapling sent him a message: Ya—Ya—Ya—
Ange didn't understand and tilted his head in confusion.
Little Sapling explained: Whitey—Has come—Whitey—Has come—