The Devil
The Spanish term 'el Diablo' translates to 'The Devil' in English. In Spanish, 'el Diablo' often refers to the Judeo-Christian figure known for evil and temptation, otherwise known as Satan. Moreover, the term can be used metaphorically to describe a cunning or mischievous person. Capitalization of the 'D' in 'Diablo' is often used to distinguish between the devil as a general concept (diablo) and 'the Devil' as a specific figure in religious texts (Diablo).
The devil is the main character in many legends.
In this sentence, 'El Diablo' refers to a mythical figure often portrayed as the antagonist in many stories and legends, symbolizing evil or mischief.
The baker calls his oven 'the Devil'.
In this context, 'El Diablo' is used as a nickname for the baker's oven, probably because of the extreme heat it generates, reminiscent of the commonly used imagery for hell.
I was told that the best party is at the 'El Diablo' nightclub.
Here 'El Diablo' refers to the name of a nightclub, a common practice is to give quirky or catchy names to such establishments to attract patrons.