With that being said. The series actually sort of kinda just finishes this plot immediately. He realizes very early on that she isn't the princess, the internal conflict switches to whether or not the MMC is using the FMC as a replacement to the princess he was protecting because he too starts gaining feeling for the FMC. Why you ask? Well, like i said these are both attractive leads in a manga so yeah....
Its kind of weird how the original plot is just forgotten. Though Resolved might be a better word. The series shifts to the MMC's rival who has come to the future as well in hopes to exact revenge or whatever to the male lead. While the male lead is getting accoumsted to the modern life and getting jiggy with the FMC.
Honestly I think this series did a poor job of making the characters have feelings for each other. I understand that both are teenager so having crushes are normal. But it still felt a bit ridiculous (Funny thing to say in a manga where time traveling is a mechanic.).
One of the conflicts of the series is between the FMC and her father who acts like an asshole. He's totally not being an asshole to play the tough asshole father role. That is 100% not what he is doing yup. So with the Male lead she escapes to the past but something goes wrong and she ends up in the wrong time. So the male lead is constantly going to the future and past trying to find where she is. While the female lead tries to understand more about where she is and how she can be more of use to the people around here.
As i mentioned one of the conflicts is The rival of the Male lead trying to kill the male lead. I liked this part. How they resolved it and the dialogue and backstory of those 2 characters were well done. Arguably thats the only thing that really stood out in the manga. I think it was dramatic and evoked the necessary emotion that the author was looking for.
The characters are... They exist. Honestly i can't really remember. I was told that the male lead is the nicest of all shoujo male leads but thats not true. He is pretty nice though. It's always nice to see another male lead that doesn't try to immediately rape the female lead in the beginning of the manga. But yeah incredibly blanket personalities. I guess they did the job. At least i don't really have any negative feelings about the characters except maybe the father who totally played the asshole and nothing else totally. There is no deeper to meaning except that he's an asshole totally.
I think some of the issue regards how the series gets a bit weird towards the end with magic hair. The fact that the time travel works almost perfectly now that the manga is almost over.
When the series does end. There is some unresolved shit like how come no one else found the time traveling portal? Or how they will handle the future. It just kinda gets thrown under the rug.
In the end I feel like Shinobi Life did the bare minimum in regards to entertainment. Like this is the bare minimum any author aiming to acheive. Though yes there were some stand out moments I don't think they are enough for me to recommend this series. Its enough for a time killer but your not missing if you don't read it.
TLDR: So much potential but really just came out ok. 5/10
