Demon Oak Quest

Start this quest with NPC Oldrak, and say to him 
demon oak
yes
bye
And now you can enter to the quest.
Once you have acquired the Hallowed Axe return to the Demon Oak and start to attack its 4 most vulnerable points:
1: The left spiked ball
2: The bird
3: The face of the tree
4: The right spiked ball
Once the tree is 100% dead, you may leave again. Upon exiting the area you will receive the following message:
Tell Oldrak about your great victory against the demon oak.
Thus, speak to Oldrak again to tell him you have defeated the Demon Oak. Once this is done, go to a grave stone which is located south of the infected area with the name of "Yesim Adeit" (Which can be read as "Yes I made it").
"Use" the grave stone to enter the rewards room and choose your reward.