In (the) blazes? American phrase informal mainly US
When used as an intensifier following a question word (who, what, where, when, why, and how), the phrase expresses severe perplexity, surprise, or annoyance.
What in blazes did you do that for? Were you aware of the danger?
How in blazes do you expect me to do that? I'm at my wit's end.
What in the blazes is happening? Somebody narrates.
To make someone understand how serious, difficult, or dangerous something is
Used to emphasize what you're saying
To emphasize or focus on some topic, issue, or aspect.