The Red Track by Gustave Aimard

Ambition is the most terrible and deceptious of all human passions, in the sense that it completely dries up the heart, and can never be satisfied.

General Don Sebastian Guerrero was not one of those coldly cruel men, solely governed by the instinct of art, or whom the smell of blood intoxicates; but, with the implacable logic of ambitious persons, he went direct to his object, overthrowing, without regret or remorse, all the obstacles that barred his way to the object he had sworn to reach, even if he were compelled to wade in blood up to his knees, and trample on a pile of corpses. He only regarded men as pawns in the great game of chess he was playing, and strove to justify himself, and stifle the warnings of his terrified conscience, by the barbarous axiom employed by the ambitious in all ages and all countries, that the end justifies the means.