Ichiriku Orihara is an Assistant. He works with Ashirogi Muto twice, once when working on Run, Daihatsu Tanto! and returns to be an assistant again when Pefect Crime Party is published.When Tanto was cancelled he continued to work for Muto Ashirogi for free because he loved working with them.
Orihara has pointed short black hair, always styled upwards in a number of spikes sticking up and forwards from his scalp. He normally wears a headband and gloves, and typically wears sports-type clothes, such as cycling shorts, track suits and similar. Physically he is very skinny, both his arms and legs typically drawn as thinner than the majority of characters. He also often emphasises his feelings with body language, such as sticking his hand up with the arm completely straight in a swift, sudden jerk while asserting something. He is almost always seen smiling, which shows his positive personality.
Orihara is very excitable and energetic. Ironically, despite the energy which makes him stand out from many other members of the cast, he describes himself as an 'ordinary guy'. He is very enthusiastic for his work, cheering and whooping upon completion of a chapter during his first appearance, and is very excited to be working with Kawaguchi Taro's nephew, reading all of Super Hero Legend before coming to work on Tanto, as well as being thrilled to be working alongside the author of Business Boy Kenichi, referring to Takahama with the suffix '-sensei' despite Takahama now just being a fellow assistant.
Orihara is also very loud, typically shouting or at least raising his voice, though this usually is just because he is so excited about everything. As the regular assistant characters go, Orihara is largely a comic relief character, his over-excitement and enthusiasm often providing comedy within the series. In terms of the group working on the two series he works as an assistant on, however, he is typically a positive influence, always being bright and keen and always being keen to learn from everyone else in the room. He does not seem to take it personally when others do better than he does, only wishing to learn and improve for himself.
Orihara first appears in the series as the new assistant Miura finds to work on Run, Daihatsu Tanto once it gets serialised, working as the only other assistant alongside Takahama. Orihara's personality initially makes him stand out among the group, and his addition means that they will no longer have to worry about the office being too quiet while they work. This is immediately evident, to the extent that Takagi has to assure Miyoshi that she will not be overshadowed by Orihara. Orihara continues to work as an assistant throughout Tanto's run, and his reaction to the news that Takagi and Mashiro are quitting the series is typical of his attitude: he immediately raises his voice in confusion, wanting to know what brought them to such a decision. However, after hearing their reasons, he feels inspired, and offers to work under Takagi and Mashiro even while they are not serialised. He quickly assures them that he will get another job so they won't need to pay him, but asserts that he still wants to stay and work with them and to continue to learn from them despite their decision. His loyalty and passion are clear, and the pair gratefully accept his continued presence.
When Moriya and Shiratori are hired as assistants, Mashiro assess them alonside Orihara to do an undersketch of backgrounds to decide who will be drawing and the other two will be inking and finishing touches. Orihara takes 15 minutes longer to complete his than the other two and Mashiro chooses Shiratori and Orihara is happy for him.
After hearing that Shiratori was working on a name too, he was shocked but after reading it thought it was great. After Takagi's revisions, he asked him if he would look at a name if he drew it. Later, he informs Mashiro that they are getting faster at finishing chapters of PCP. When Shiratori and Moriya show their names to Hattori, he panics and thinks that he should write something too. He leaves then and trys to cheer up Moriya. When he heres about Takagi being the author for Shiratori's manga, he is shocked and asks if he is wondering to have it win in treasure then run in Jump weekly. He then tells Mashiro they will be done a day early every week from now on. He is later seen rejoicing about the results of Rabuta & Peace.