User blog comment:Ash9876/Standard Magic and Lost Magic. Pros and Cons/@comment-3413183-20120127042113/@comment-3030647-20120127065433

Well, it depends on the secret arts and how he uses his magic in proportion. I mean, it's not like it WOULD kill him if he used it properly. But, if you read my Blood Dragon Slayer Magic, you can see that a single secret technique shortens down the user's lifespan to 7 more years, and 7 years ONLY, so yeah.