Soon after, Mu You followed the Tree-man and left the World Tree.
He originally wanted to look around in Emerald City, but the Tree-man followed him like a thief, popping up 'no passage' text wherever he went.
As for setting up a teleportation array, don't even think about it. 'Dark Transfer' literally has the word 'dark' in it and it belongs to the dark magic. Placing such a teleportation array under the World Tree, which represents life, is likely to get him beaten up by the elves.
Having nowhere to go, Mu You had to follow Little Ya back to her forest.
[You have left the 'Pea Breeder's backpack and returned to the 'Pea Tribe'.]
'Pea Tribe' is the name of the area Little Ya governs - it's a name she came up with, and it's been accepted by the system...
[You have released the Reconnaissance Beetle to gather information from the forest on your behalf. Investigating...]