Key for Green Door

[gcob]

Where is the key to the green door in the Mansion. I have gone through the right door and the left door but I can't find a way into the green door.

[Indinera]

Have you killed Elder?
And the skeleton?

[gcob]

I have killed the elder. Where is the skelton?

[Indinera]

If you enter the door north of Elder, you will enter a new room with a locked gate, that you must open, clicking on the middle column near the said locked gate.