The phrase 'かくして' carries a sense of concluding a sequence of events, similar to 'thus' or 'and so' in English. It's often used in storytelling to mark the culmination of preceding actions, giving a sense of finality or inevitability to the outcome.
In classic literature like '夢十夜', you'll find it employed to gracefully tie together narrative threads. Modern light novels might use it more dramatically, emphasizing how small choices lead to major consequences. The beauty lies in its versatility - it can sound poetic in period dramas yet perfectly natural in casual anime dialogues.