Before I found this オオカミちゃん, my go-to recommendation for absolute beginner readers was レンタルおにいちゃん. (It’s now my number two recommendation.)
I consider the following to be pros of the series:
- The main character is young, so there’s often not difficult dialogue.
- The situations/scenarios are typically simple to follow.
- Not really any specialized vocabulary.
- The material slowly gets more difficult from one volume to the next.
- The series is complete with four volumes.
For anyone attempting to read the series, I recommend utilizing the WaniKani book club.
Summary of what the series is about.
両親の他界…優しかった兄の豹変…独りぼっちで傷ついた少女は昔の兄の優しさを求め、“おにいちゃん”をレンタルする―――お金で。「レンタルでも、私は“家族（ぬくもり）”がほしい。」
Her parents have passed away… Her kind big brother has changed completely… A girl, alone and hurt, in search of the kindness of who her brother used to be, she rents a “big brother”…for money. “Even if it’s a rental, I want family (warmth).”
Little Kanami has lost the warmth of family at home, following first the death of her parents, and second her once-kind big brother becoming distant and abusive. She lacks the warmth of friendship at school, where classmates either bully or ignore her. When things seem to be at their worst, Kanami meets Makoto, a young man whose kindness is exactly what’s missing from her life. Makoto, seeing a reflection of his own childhood in Kanami, offers a proposition: any time she’s feeling down, she can rent time with him as a big brother.