Watabe has short brown hair and wears glasses.
Watabe is Izumi Miyamura's stalker who will go to great lengths to take pictures of Miyamura, the majority of which are taken without Miyamura's knowledge. However, this seems to be limited to school only, he does not seem to intrude on Miyamura's home life. His collection of photos is unbelievably large. Though according to himself, Watabe just has an usual interest in Miyamura, but not to the level of liking him. Everyone is aware that Watabe is stalking Miyamura, including Miyamura himself.
In addition, he is seemingly observing Miyamura at all times, and knows things that even Miyamura doesn't know. For example, when Miyamura's slippers went missing, it was immediately assumed that Watabe took them. This turned out to be false, as Watabe knew that Miyamura misplaced them in a different shoe box. Though when asked how he knew that, all Watabe said was "Because it's Miyamura's?"
Unexpectedly, when Miyamura isn't around, Watabe is a completely normal student. He does not act stalkerish or suffer from any Miyamura withdrawal. Of course, the moment Miyamura is around, he goes back to his normal ways.
Miyamura does not appreciate being stalked. However, so far, he has never asked Watabe to stop. But this may be because Miyamura is probably not fully aware of the extent of Watabe's actions, as he has never seen the full photo collection. Any time Miyamura calls for him, Watabe will immediately come over, even before Miyamura finishes saying his name.
Watabe has no ill will towards Hori. In fact, he thinks that Miyamura having a girlfriend somehow makes him even better. Hori, on the other hand, is extremely cautious of Watabe, considering him one of the mostly likely candidates to take Miyamura away from her. According to Hori, his name is spelled "Watabe", but pronounced "pervert".
- The name Ichirou means "one" (一) (ichi) and "son" (郎) (ro).
- Ichirou's surname Watabe means "handing over" (渡) (wata) and "department" (部) (be).