Even if Krans wanted to breathe, they still couldn\'t.
A silicon-based life form means that its molecular building blocks are silicon-based. Human beings are carbon-based, because we are composed of complex organic molecules with carbon backbones (think DNA, Krebs cycle, &c.).
Carbon\'s valence shell is half-empty/half-filled, so it allows for easy bonding with other carbon molecules, allowing it to form these complex chains (organic molecules). Complex structures are the building blocks of all life on Earth.
Silicon has the same properties valence shell as a carbon molecule, so people generally thought: \"Well, if carbon-based life forms exist, why not silicon-based life forms?\"
BUT, and this is a large but:
The silicon atom is larger, and so its bonds with other elements are weaker. Just look at what happens when two oxygen molecules bond to carbon/silicon; in one case we have carbon dioxide, in the other, sand.
So basically, Krans wouldn\'t be able to breathe (at least, not the air that a human could breathe), and if it didn\'t breathe, it couldn\'t possibly have any use for blood. Of course, a Kran would be incapable of having complex structures like a cell, because of silicon\'s chemical properties, so it would be impossible for them to have muscles, or any means of physical locomotion other than being pushed by the wind.
Pure silicon forms into crystals, eventually, with enough heat and a silicon-seed. The crystals would be extremely abnormal, so it doesn\'t make much sense that they could all just grow into humanoid shapes.
Of course, this is a fantasy world, and anything goes. The Kran would be a being of magic, or something. Science plausibility doesn\'t need to exist in video games -- of course, if it does, things make much more sense.
The point is, the Kran couldn\'t possibly have lungs (since they lack the basic properties to be able to have cellular structures). As well, they wouldn\'t eat normal foods, since as a silicon-based life form, their metabolic processes would be based on silicon-based molecules, rather than carbon-based molecules (like a human). And since the Kran can\'t have cells, once again, due to the chemical properties of the silicon atom, it can\'t have blood cells, it can\'t possibly garner any use for oxygen (which is used in human cells). So, in short, Krans could not breathe. Nor would they have blood. Unless, of course, they had it for no reason. \"It\'s a sort of magic!\"
So thinking of a Kran in any way approximating a human would be absurd in any scientific sense. You\'d have to either blame magic for what they are, ignore the chemical/biological properties en masse, or somehow change what they are to afford for these errors.
Then again, it\'s fantasy. People can think up whatever they want.