Translations will always differ because different translators choose to use lexical ambiguity to emphasize different aspects of both language and poetic communication. For example, if someone wanted to capture what they felt would be Poe's emphasis in English into another language, the exact wording between translations might differ. Keeping things in the most simplistic sense, "seguido" means "followed." It comes from the verb, "seguir" which means "to follow." The Spanish word for "fast" is "rapido." This means that the first part of the verse could be translated as "seguido rapido," literally translated as "followed fast." To reflect comparative speed, there is no suffix added to the word as in English. "Fast" becomes "Faster" in the English language. The descriptor "mas" is added to emphasize and reflect comparative speed. This means that a translation of "followed faster" would be "mas rapido." The inclusive conjunction in Spanish is "y." Putting everything together, the translation of the verse becomes, "seguido rapido, y seguido mas rapido."
From a strict translation point of view, this captures Poe's words in Spanish. The text of the poem stresses the idea that disaster without mercy attached itself to the master in a rapid and successive manner. "Seguido rapido y mas rapido" communicates the idea of followed with speed and followed with more speed. This translation could be a direct approach to moving Poe's verse from "The Raven" into Spanish.