Since I don't know the exact story, it could potentially be about a figure who met a watery end and was considered beautiful in a way that defies normal expectations. It could be a story about love and loss, where the person who drowned was remembered in a special way that made them seem the most beautiful. It might also be a story with a moral or lesson, perhaps about the transience of life and the power of memory.
One possible theme could be the concept of beauty in death. The idea of the 'ahogado' (the drowned one) being the most beautiful might imply that there is a certain allure or significance to the state of death.
I'm not entirely sure what'mas black bottom based on true story' specifically refers to. It could potentially be a movie or a play. If it's a movie, it might be a story that is based on real - life events and set in a particular place or community. Without more context, it's hard to say exactly.
In a cultural context, if 'el vate bases on el dasa story', it could mean the preservation of certain cultural values. 'El dasa story' might be a traditional story that contains important cultural elements. 'El vate' then becomes a way to carry on these elements. For example, if 'el dasa story' is about family loyalty, 'el vate' could promote the same value in a different form.
A scary El Salvador story is that of the Xtabay. It's said to be a female spirit that lives in the jungle. She sings a beautiful but hypnotic song that draws men to her. Once they are close, she either kills them or drives them insane. This story was often told to keep people, especially men, from wandering too far into the dangerous and uncharted parts of the jungle, as the unknown held such terrifying entities.