Naoki Kawaguchi

Naoki Kawaguchi (川口直樹; Kawaguchi Naoki) was a former 4th Division lieutenant that later was promoted to the Royal Guard.

Biography
Naoki has been a captain for a long time, even by shinigami standards. Few could recall that Naoki gained his position through numerous recommendations by other captains of the time, which boosted Naoki's reputation as a responsible though somewhat relaxed captain. He was originally a typical shinigami combatant, but helplessly watching the deaths of his friends while on a training mission caused Naoki to begin studying the healing arts, in hopes of being able to prevent others from having to suffer from what he had to suffer.

His diligence in helping others earned him respect from several captains, including the previous Fourth Division captain. Naoki's skills developed further, and he gradually began receiving captaincy recommendations. For some time, he questioned these recommendations, seeing that the Gotei 13's captain ranks were filled, but the Fourth Division captain announcing that she was stepping down resulted in him accepting the recommendations and became the next Captain of the Fourth Division.

As the Fourth Division Captain, Naoki's reception was mixed between those who were disappointed at the previous captain's resignation and those who welcomed change within the division. Naoki gradually became accepted and respected by his division members, after countless instances of his skills saving shinigami.

Personality and traits
For centuries, Naoki taught his followers that medics often find themselves torn in their duties: they had to leave behind the shinigami beyond saving to save themselves and the ones who were capable of being rescued. "Compassion is good for a medic, but too much compassion will get you, and your friends, killed." Naoki is difficult to surprise, both in and out of combat, though he does his best to address the situation presented to him. He has been often seen as the neutral ground in disputes, though Naoki never considered hearing out a hollow.

Powers and abilities
Naoki's array of skills are standard for a shinigami, with the exception of being his focus in kido. As the Captain of the Fourth Division, Naoki is highly proficient in the usage of the healing arts. Add to the fact that he created and developed acupuncture techniques, utilizing one's pressure points to heal or incapacitate a target at close range. Naoki prefers to fight using the kido arts, which indicates that he is skilled in using both bakudo and hado forms.

Shikai
"Look away, Mizuwamaru!" The blade transforms into a watery substance that reflects material off of it. It is effective against both physical and non-physical material and waves, allowing Naoki to produce protective barriers around allies and enemies (as well as selectively choose who or what can pass through his barriers). However, there is a limit as to what the substance can resist, making the ability unreliable as an absolute defense.