Board Thread:Questions and Answers/@comment-5774380-20150511135448/@comment-25933906-20150511151122

That's a good point Manuel. Probably Titan Shifter can be created at will. For example when [SPOILER] Eren bit the bottle labeled "Armor, Braun". Rod reiss had cataloged the titan serum into branches with the name [ESPECULATION] of their futures users, or maybe things like that.