The first five chapters are a hilarious and thoroughly enjoyable intro the the story deserving of a 10/10 rating. We see the hellish training that Usato is subjected to by Rose, based on the simple idea that healing mages are capable of healing their own bodies which means they are capable of going through a much more strenuous and damaging regimen than most people could handle. It's hilarious seeing Usato's mind breaking as he's basically subjected to torture and as his physical capabilities become more and more inhuman. His sense of what's normal has been warped and even though he knows that he's gone through intense training, he doesn't seem willing to process just how ridiculous and abnormal it truly is. Several times, it's emphasized how glad Rose is to have found Usato--someone who has both a capable physical body and a tenacious spirit, who she can trust to not die on the battlefield.
I don't really like Bluey. And in some ways, the introduction of Bluey as a character marks the transition of this manga from an excellent story to a solidly good story. The original novelty has worn off, which I think was a large part of what made its beginning so great. After the initial intro, there is more training and even a battle where we see the healing mages in action. Then we get into what will be likely be the longterm plot: Usato and the heroes will go to deliver letters to various other countries asking them to be their allies in the inevitable war against the demon king and his forces. First, they go to Luqvis Magic Academy (ch. 17-27) where there is a bit of a Karate Kid type plot. During their travels, they will enter villages and cities which will each have unique problems they can face. This will allow the story to have a series of largely unrelated side stories which are connected together by the goal of trying to gather allies for a large fight. It's a pretty decent set-up. Also, they'll probably have Usato continue to experiment with healing magic and how he can apply it in new and different ways that healing magic isn't supposed to be used. For example: he punches people while simultaneously healing them, he blinds opponents with a flash of light from the release of his healing magic, and he is in the process of developing a way to throw a ball of healing magic for a ranged attack.
[Reviewed at chapter 31]