In the world of Naruto, and this AU, Legendary missions are missions which allow for people to gain a Limited Technique In Character. There are many Limited Techs that can be claimed through this Method. Although after claiming the Hidden Scroll you must learn the Tech outside of the Mission.
-Legendary Missions Do not offer KKG's of any kind, Nor Jashinism, or Elements.
-Each Legendary Mission is only obtainable by Ninja who have found or been awarded a "Legendary Token" These are Tokens which are used much like the Starting Tokens and S Rank Tokens. Using These you will be able to ask for a Legendary Mission.
-The mission must be Made by Staff and NPC'd by Staff for a Ninja to be approved for the Tech being claimed.
-All Limited Tech's still have basic Rules to follow. Such as trying to get a Limited Tech that is only for ninja who had Medical as their Main Spec and you do not have this main Medical Spec means you can not learn this jutsu, At All.
-Limited Techs also have Rank requirements just like the Legendary Missions will not allow a Genin to take these missions. But they can be accompanied by a higher ranked ninja to gain said Tech.
-Techniques that are clan limited like Demonic Ice mirrors or MS and EMS, Some can be gained IC through the correct means, Jutsu of the Clan can be claimed through Legendary Missions as well and only if it is your clan.