Seemingly always calm and composed, never showing much emotion, Satoshi Hiwatari is a very distant, cold, and silent character,
though these qualities never seem to affect how close he keeps to Daisuke Niwa. He is extremely intelligent, having graduated
from high school at eight and graduated from Lagoon University at thirteen. However, he attends Daisuke's Junior High School,
saying to Daisuke that he does so in an attempt to have a normal life. The reasoning for his ambivalence towards others is
unknown, though most of the girls except for Risa and Riku like him. A possible reason behind his lack of willingness to develop friendships is his worry regarding Krad: if he feels emotion for anyone, Krad will attempt to use or kill that person.
He is the police commander in charge of capturing Dark, and due to his family legacy, he is almost obsessive in his attempts
to capture the phantom thief. He is the sole living member of the Hikari family, whose artwork is almost always Dark's targets
for stealing. He was adopted by a 26-year-old police officer whose family name is Hiwatari, so his name was changed to reflect
his adoption. During the course of the story, he begins to care more about Daisuke's safety. It appears that Daisuke is the
trigger for Satoshi's other personality, Krad, to appear. Satoshi opposes Krad taking control of his body greatly, and has taken on an uncaring personality to 'seal his heart,' and thus, Krad. Krad is Dark's "evil twin", or opposite, a homicidal blond whose only motivation seems to be getting rid of Dark, Daisuke, and
anyone else that comes between him and Satoshi.
Satoshi and Risa share a small glance at the end of the anime that some people have interpreted to mean that there is a
possibility of a romantic relationship between the two of them. In the manga, the two of them have many interactions later
on, though most of them involve their mutual interest in Dark.
There are many hints in both the anime and manga that could be interpreted as him having deeper feelings for Daisuke, such as the fact that Daisuke is the trigger for his transformation into Krad. Given that Daisuke turns into Dark because
of romantic feelings, one would assume that Satoshi's curse works the same way, but many also have a theory that because Krad
is opposite of Dark in all ways that grief, sorrow, or depression and possibly even pity may trigger the transformation. Both
theories have not been proven
His (adoptive) father is the Chief of Police, and they are investigating Dark. Satoshi is also the Commander in the investigation
of catching Dark. His original surname is Hikari, and his family has been at war with the Niwa family for centuries. The only
person he intentionally seeks out is Daisuke.
In the later books (eight, nine, and ten) Satoshi seems to hint that either he or Krad killed his mother, Rio Hikari.
He knows that Daisuke is Dark, yet he befriends Daisuke. He has said in the manga that he has no more "time." Knowing that
Argentine has captured Risa, he offers to help Daisuke in the rescue attempt, as he knows where Argentine resides.
He has a college degree, which he obtained at age 13, (he graduated high school at age eight) but still attended Azumano
Middle School with Daisuke -- apparently to get "closer to him." (see Volume 9) He later withdrew, supposedly to create distance
between Daisuke and himself.
He wears glasses even though he doesn't need them. His eyesight is fine, not to mention that his observational skills are
impressive. He records his observations in a small black notebook. It is hinted that his glasses might be a barrier against
Krad appearing, as whenever Satoshi turns into Krad, his glasses shatter or fall off.
His true last name is Hikari, whose meaning is debatable. Although in the Japanese manga it is written as Hi-kari[氷狩],
in the anime, there have been implications of it being synonymous to 'light'[光]. Most translations of the kanji for
Hikari translate the name as 'ice hunter.