Unknown writing

Titan Writing is an unofficial title used to refer to the yet unnamed and unintelligible writing or code on a can of herring in Castle Utgard. So far, the series has provided very little information on its origin, use, or true nature, but it is known that the writing can be read by at least Ymir, though it is possible there are more characters capable of reading it.

Form
Titan Writing appears as block-like code but contains some inconsistencies in its multiple appearances. In its first appearance in which the series directly reveals its existence, though still nameless currently, the writing appears partially almost like Japanese hiragana or katakana. Upon closer look, the characters are partially covered in shadow but one clear character can be seen, appearing like the letter Z or hiragana's ko syllable.

Appearances
During Ymir and Reiner Braun's conversation in Castle Utgard, Ymir reads the mysterious writing on a can, which Reiner brings to her attention. However, the conversation is cut short by the pending attack of Titans on the castle. Reiner states that he cannot read the writing at all. Perhaps suggesting the 'warriors' from outside the Walls, Annie Leonhart, Bertolt Hoover, and Marcel, cannot read the writing either.