You are
A die (or several dice)
Give me a fruit, I'll turn it to pieces,
Dicing a fruit (or a vegetable) is cutting it into pieces.
A turn of bad luck, and your plan ceases.
"No dice" is an expression meaning there is no possibility of something.
Mistaken for death, if I'm without friends,
A die (the thing we throw) can be mistaken for the word die (the thing about dying). When there are several, we talk about dice, which clears the misunderstanding.
Bringing with a breath, success will I send.
Some people like to blow on dice they're about to throw for "good luck".
Let's not forget, the adventurer's quest,
Eyes of the snake, and they'll become the best.
In role-playing games, dice are more than often a central part of the gameplay mechanism. A "snake-eye" is the worst result you can have (it's basically two 1).
Also,
The first letter of each line spells out "Gamble"