D3 is a dimensional supervisor, specifically the supervisor of the 3rd dimension. He serves Lady Tokimi and the other Chousin (Tsunami directed an order to D3 about the state of Tenchi's powers during his battle with Z). He first appeared before Dr. Clay when he arrived to demand to see Tokimi to make his report and confirm the person that she is searching for. Although D3 pointed he could also confirm that person, he immediately disappeared when Tokimi agreed to Clay's terms of speaking with her. After Tokimi ordered Clay to bring Washu to her, D3 pointed to Clay not to hurt Washu.

After Dr. Clay's capture, D3 is surprised to see that Tenchi Masaki is capable of matter conversion, but is only capable of generating three lighthawk wings. D3 also applies the necessary treatments on Dr. Clay and his robot servant Zero (who was merged with Ryoko Hakubi) in order to block off all memories pertaining to Tokimi to help conceal her existence.

D3 is also aware that Z is planning to disobey Tokimi's orders of not harming Tenchi. D3 later observes Z's final battle against Tenchi with the other interdimensional directors.