In a Live letter when YoshiP went into more detail about Scouting class, he used Thief as the Base class and Ninja as a possible Job for the Thief. Thief as a Job would be wasted as it gets only 5 usable skills. Its better off as a Class where it controls the main skills the Ninja will use as well as all the traits for the job. Ninja can feed off of Thief's skills with 5 core job skills just for it.

The group Thancred used to be with (never classified as thieves but as criminals) would be the starting base with Yugiri passing on her knowledge to help solidify the class (As in they will both be part of the same class with Yugiri completing an unfinished style). Later on Yugiri will impart a Job stone by showing interest into her Doman ancestry.

As for some reasoning with what ever guild being the base class, Thancred's base class will change from GLD to what ever the new class is. All of the members of the Scions are in the base classes. Yda is a Pugilist, Papalymo is a Thaumaturge, Ysholt'a is a Conjurer, Urganeir is an Arcanist. Thancred, like his brethren, will adopt the new class as his so if its a Thief guild, he will be a Thief Class with the addition. If its named anything else, Thancred will be what ever it is named.


Also don't expect to get Yugiri's AoE skill...We don't have Ysholt'a's Shield skill as Conjurers. The key NPCs have skills we may never have.