Halo: Blood Line isn't really bad, it's just not good. There's a lot to not like here, and it outweighs the like factor. Some major points:
Nothing in this series has any affect on anything in else in the Halo universe. We're dealing with some random lost cruiser, some vaguely missing Spartan team, and at no point will the plot ever actually do anything to affect the universe at large.
The writing and art barely work together. In several complex action pieces through the series, I was totally lost. Characters were saying whatever they felt like saying that moment, the art was bouncing around between characters with no sense of direction, and I was unable to piece together a complete scene in my mind. There's a sniper somewhere, and he's shooting at... something... somewhere. And then... wait, I was picturing that guy as being up higher. I have no idea who's where or what they're doing.
The comic is a series of cliches. There have been two Monitor characters in the Halo games, 343 Guilty Spark and 2401 Penitent Tangent. Let's work together to name a new Monitor, shall we? We need a number divisible by 7, so let's try 686. The name is some colorful word for a feeling, combined with a science-y word, let's try "Ebullient" and "Prism". That's actually the absolutely cookie-cutter name the writers actually used for the Monitor in this story- 686 Ebullient Prism. Yawn. Also featured, for instance, is a moment when the lead AI character appears in a big-eyed anime rendition. Why? Probably because the writers couldn't come up with anything remotely original, so they made her look like an anime character in the middle of an otherwise serious comic book. Laugh-out-loud funny, right? (Yawn.)
The end is a non-ending. Or rather, an incredibly sappy and forgettable one. You might need some extra water for reading the final issue of this comic, to wash off all the sugar that's encrusted to the pages. I literally rolled my eyes as I quickly closed and filed away the comic.
So if you're thinking about picking this up? Don't bother. Issue #1 is okay, but things just get exponentially worse as the series got on. Overall, I wouldn't invest in any of it.
And come on- the characters have to have numbers engraved in their faceplates, because the writers couldn't figure out any better way to differentiate them in the story? That's just plain lazy.