Appearance and Personality
Mamoru has deep-black eyes and brown hair, and wears a yellow long-sleeved shirt with tints of orange running down his collar into the bottom at the middle and at the sleeves, yellow pajamas with orange edges at the ankle portions and brown slippers with white socks.
Mamoru tends to be secretive for the most part and for this reason not much is known about him. However, despite his shy nature, he is actually a friendly individual who can make friends with people in his own age group effortlessly; his friendship with Lan is a noteworthy example in this regard. On the reverse side however, Mamoru is quick to losing traces of optimism which forces Lan to knock some sense into him by reflecting the similar situation to that of Hub's.
Mamoru, in many aspects, is a more-than-meets-the-eye character in the series. An example of this is the fact that he is readily analyzed as physically defenseless on the account of being in a wheelchair, since his diagnosis with HBD, is countered by his status as the Undernet's administrator.
Yai Ayanokoji falls on the loser chute after losing the N1 Grand Prix, suffering a major blow to the head in the process, and is sent to confinement at the Seaside Hospital, swearing to hold Sunayama liable for the incident, or the way she puts it, to "sue Sunayama for all he's got!".
Yai soon receives the company of Lan, Mayl and Dex at the hospital and complains of boredom and the length of stay in her room. She then requests Lan to fetch some tea for her at the hospital's lobby. Lan begrudgingly does so but as he is about to finish getting tea, a nurse approaches him and inquires him if he has seen some individual in a wheelchair named Mamoru in the premises. Lan, at the nurse's request, puts behind Yai's request for the moment and searches for him. Sure enough, Lan finds Mamoru at the shoreline and the two begin making friends with each other. At that moment Lan witnesses another strike of HBD in front of his very own eyes in form of Mamoru's worsening condition. Mamoru is quickly sent back to his room for diagnosis with Lan trailing right behind him. Because Lan's NetNavi, MegaMan.EXE, had originally been Lan's twin brother Hub and thus had died from HBD, the NetNavi immediately recognized the symptoms upon witnessing it.
No sooner after Mamoru recovers, Lan promises to visit him the second time and heads back to Yai, who impatiently asks him where he has gone.
Lan visits Mamoru on the beach for the second time as promised. This time, the latter yet again suffers an HBD attack. Seeing this, Lan re-enters the hospital and finds Mamoru's doctor, taking him and a nurse to assist Mamoru. This attack lands Mamoru in the emergency room, but he did not want to have surgery; his nurse tells Lan that he has undergone surgery three times, all of which were unsuccessful. Mamoru has no hope that a fourth surgery can solve his problem, even though it is a new kind of surgery for HBD; upon hearing this, Lan encourages Mamoru by giving him the rare Battle Chip he wanted, IceBall M.
Mamoru's condition gets worse three days later and he is sent to the emergency room for his fourth surgery. However, it is interrupted three hours later by Anetta, who disguised as a nurse, uses her NetNavi PlantMan to make the growth function of the Tree of Life malfunction and create vines throughout the hospital to render most of the hospital's facilities useless and find a TetraCode for Wily. After MegaMan defeats PlantMan, the Tree of Life returns to normal and Mamoru's surgery is successful.
Lan later on comes across the sinister source of the Undernet at a hidden elevator located past the hot spring at the Ura Inn; it is revealed that Mamoru is the Undernet's administrator, much to Lan's bewilderment. Mamoru then explains his father's involvement in the Undernet's creation, and the "Giga-Freeze" program, which is capable of subduing Alpha but can be dangerous in the wrong hands. Not long after this, the SciLab is infiltrated by none other than DrillMan.EXE, who after stealing Alpha therein, escapes via a distorted portal he himself had just created into the Undernet.
In the recent wake of MegaMan's demise after destroying Alpha, Mamoru - along with Mayl, Yai, Sean, Dex and Chaud (Tora would have appeared with the rest of them had it not been for the fact he went back to Swapopolis beforehand) - finds and comforts Lan on the Seaside Beach, thanking him for giving him courage to face his disability, adding that if he didn't become his friend, he would still remain alone in the hospital.
Mamoru heads home after this, but it is now assured he has been cured of his long-standing disease. A scene in the end credits further supports this which shows Lan giving Mamoru a PET, suggesting that he was well enough to NetBattle.
Mamoru is Japanese for "protect", and Urakawa literally means "inlet river". His surname is shortened as Ura in Japan, which can mean "reverse" or "backwards". Mamoru's full name in English literally means "protect inlet river", which is actually quite accurate given his status as the administrator of the Undernet and his attempts to keep it as a secret even among his friends, notably Lan, who eventually learns of its existence anyway. The Urakawa in his name might be also a reference to the Undernet, which in the Japan versions of the game is called "Uranet" or "Ura Internet". Beeing the internet itself compared to a river of data, the Undernet is a flow of information underneath the main, superficial flow of information.
Urakawa is also a town in Hidaka Subprefecture, Hokkaido, Japan.
- Fan theorized that Serenade.EXE was Mamoru's NetNavi, since Mamoru's father created the Undernet and Mamoru has an emblem on his wheelchair very similar to that of Serenade. This would late be indirectly confirmed by Masakazu Eguchi. 
- While not mentioned in the games, according to the Rockman.EXE no Himitsu - Official Settei Illustration Guide, Mamoru is the nephew of Tamako Shiraizumi. Mamoru's mother, Kimie Urakawa, the owner of Ura Inn, is Tamako's older sister.
- Mamoru did not make an appearance in any of the games following Mega Man Battle Network 3.
- ↑ https://www.therockmanexezone.com/interviews/2018/03/21/exe-15th-ann-special-staff-discussion-part-6/ Eguchi: “I’ll leave that to everyone’s imagination… Let that be my answer please. However, I think that the person everyone is thinking of is probably correct.”