Shichirou - Character Analysis
Shuichirou is an extremely kind-hearted man who prefers not to openly express his feelings. He is very introverted and sceptic by nature about a lot of issues, and due to this, he appears to be a cold person at first glance.

Along with his "untouchable" aura comes a very calm personality, which shows in that he is never easily disturbed by anything - or at least he doesn't let people around him know. Indeed Shuichirou isn't always as calm as one might expect and he would like others to think. The incident concerning his stepmother, which occurred years ago, emotionally stirred him so strongly, that he is now quickly irritated by anything that cannot be explained rationally. (=scientifically)
Therefore, it takes him quite a bit of time before he accepts that Kohaku is indeed a true angel.
It seems as though ever since his stepmother left his life, he has been forcing himself to surpress the idea that supernatural things exist, and Kohaku's sudden appearance automatically means that he is now being torn out of his belief once again.

His generous hospitality and his gentle, caring behavior towards the children he takes care of at the hospital clearly show his kind nature.
He is very devoted to whatever he sets his mind to, and shows a lot of diligence in his profession. He obviously enjoys his job and puts a lot of effort into it.

His ways of dealing with Kohaku being rather "indifferent" in the beginning, they gradually turn into strong, loving affection as he shares his home with the angel. He soon realizes that Kohaku is the person he has been waiting for so long, who can help him find a way out of his loneliness, and forget the traumatizing experience he had with his stepmother.

When it comes to protecting things and people dear to him, Shuichirou can be extremely determined and strong. The day he found out the true identity of his mother entirely threw him out of his "normal" perception of life and its lifeforms, and he desperately tries to hold on to this person he has such strong feelings for. (However, seen in a flashback-manner, one would have to say that he merely had a "crush" on his stepmother : She was something he felt intrigued to know more about, and her fragile, mysterious ways fascinated him).

In a nutshell, Shuichirou is a very kind and loving person, who does not open up easily, but who has a lot of affection to give to those he wishes to take care of.

The reincarnated version of Shichirou bears an utterly different, yet similiar personality. He only appears in the very last part of Volume 4, which is why one cannot really say very much about him. He is less serious, and his younger age also make him appear more lively and open. One clearly notices that he is less experienced in life, and he even shows childish naivité at some points; feeling confused , bewildered and overwhelmed by Kohaku's behaviour. He of course has no idea what he means to Kohaku, and eventhough the angel notices that the reincarnation of her beloved one bears different traits of personality, he quickly realizes that he is nevertheless still "his" Shuichirou: Younger, less serious and without all the painful experiences, but likewise still kind and gentle.
(On another, rather shallow , note : The reincarnated Shuichirou is so much more stylish than his former ego. I assume this is because he is both younger and living in more modern times, given that 100 years have passed ! . . but yes, I agree...yes, this is rather trivial....)