Ichii is 2 years older than Nina and Zero. He is depicted as a kind and gentle-natured boy. He is also exceedingly polite and mature, thus making him a gentleman.
Ichii grew up with his elder step-sister, Sarasa, whom he had feelings for and whom was the only one he trusted until Zero came along. He had a rough past, but opened up more ever since the day he met Zero approximately three years ago. Later he tells Nina that he loves Zero.
In the epilogue, of the first series, ten years have passed, and Ichii has developed feelings for Rokka. In the end, he does not want to see Rokka marry another man, and so he asks her father's permission to marry her. In the epilogue of the second series, Ichii and Rokka have a daughter, Itsuki.