The Iron Blood's energetic and rambunctious submarine. She loves to play tag and acts like a child, but her prowess in battle has brought her along to many missions. She joins the Joint Military Exercise with mixed feelings. On one hand, she's worried she won't be able to play like she usually does. On the other hand, she's hoping that she'll find friends who will join her in her game of tag. A certain someone has asked U-81 to buy something, but it looks like she forgot about it already.