It is final battle

Step	Quest ID	Image	Coordination	Details
1	12656		/navi mbase_in 92/123	Completed Black-Haired Beast. In Safe Place in Northen Rising Lands, talk to Heina.
2	-	-	-	Create party, create instance and enter quest instance.
3	-	-	-	Inside, choose Use Tablet to start.
4	-	-	-	Wait until the dialog is done, you will be warped.
5	-	-	-	Wait until the dialog is done.
6	-		-	When they all channel mana is done, click on the egg.
7	-	-	-	Wait until dialog is done.
8	-		-	Kill Possessed Tan.
9	-	-	-	Wait unti dialog is complete.
10	-		-	Talk to Nyar. You will be warped out.
11	18349		-	You can also walk to jor_tmple1 170/307 to access the room behind Decorative Door. Talk to Nyar.
12	18349		-	Talk to Nyar. Continue on main quest Secret Altar.