Towa (永遠の標,''Towa no Shirube''), nicknamed "To-to", also known as Eternal Mark, is an artwork created by the Hikari family.
Towa has grey hair and green eyes in the anime. However, in a manga illustration, her eyes seem blue. She looks young (16 years old) depite her real age, 98 years old[reference needed]. She wears a long-sleeved violet dress which reaches down to her knees with ear piercings, a choker and boots in the same color. After joining the Niwa family, she dresses as a maid.
Towa first appears at the end of Stage 2, Part 3 (vol. 5) to help Daisuke after Dark was sealed in a mirror. Towa has the ability to find items, so she finds the mirror Krad had thrown into the ocean again and gives it to Daisuke because he looks "cute" to her. She makes a deal with Daisuke: if she becomes his guide in the mirror world to find Dark, the boy will have to find his way out without her help, Dark will carry her and she'll be cherished as a precious artwork in the Niwa home.
Entering the mirror world gives her the appearance of a small bird, and she uses it to stay close to Daisuke during his quest to bring back Dark. Gradually losing her energy, she guides and gives clues to her partner without ever telling him about her state.
As Daisuke's researches come to an end, exhausted by the trip, Towa is about to die and faints, but Dark comes back to his host at the very last minute and kisses her back to life, much to her delight. After apologizing to Satoshi Hiwatari for joining the Phantom Thief's side, she decides to follow Daisuke to the Niwa household, where she becomes a maid and assists Emiko.
Even if she holds a minor role after her main arc, she appears regularly to help the family, particularly to relay information between Daisuke/Dark and the rest of the family. For example, when Dark enters the Second Hand of Time's universe to rescue Daisuke with Risa and Riku, she is able to track Dark and notice that he isn't alone. In the same vein, after Risa is kidnapped by Argentine later in the story, Towa can sense Riku's health and informs Emiko and Kosuke.
Towa has the ability to shapeshift into a bird at will and find lost items.
Towa first appears in the anime when Daisuke asks for her help in order to save Dark, Risa and Takeshi Saehara, but as a result uses too much energy. So in return for helping Daisuke, Dark gives her some of his energy and brings her to Daisuke home, Towa choses to live in the Niwa household. She assists Daisuke and Dark when possible in their work, enjoying shopping and cooking with his mother.