How hard is the Princess No expedition?

i guess the dmg effect coupon expires; the skin will be changed permanently; unclear....

Stop Princess No Event

August 13 - September 9
Requirement: Lv. 140 or above

Accept the quest '[Sengoku Era] Stop Princess No!' from the event notifier on the left side of the game window.
Defeat Princess No in the Princess No Expedition to receive a special Princess No Damage Skin (Expires after 30 days if it isn't used, untradeable).
Defeat Princess No 10 times to receive a permanent Princess No Damage Skin (permanent, untradable, this item is not consumed when used and can be recycled).
http://maplestory.nexon.net/news/updates...princessno

not a great "guide" but the information & tips provided are good.
http://www.southperry.net/showthread.php?t=74814