But whether there are some ambiguity in the first sentence? I mean if the adjectives are too many, will it make people think the "adverbial modifier" is only attached to the last adjective? I mean they are only wicked in nature, but they are not foolish and greedy naturally? If you can't understand, I will rephrase the sentence as follows : they are foolish and greedy. And they are wicked in nature. Maybe "in nature" is not a good example, but I just hope you can understand!Neither of the sentences you give sound natural. A better position for both phrases would be at the end of the sentences. 'They are foolish, wicked and greedy in nature.' This would sound even more natural as something like 'They have (or exhibit) a foolish, wicked and greedy nature.''They became monsters in no time.'