Vishwamitr is considered to be one of the most powerful sages in our ancient text. He was so powerful that he once started creating his own parallel universe and had to be stopped by the Gods from doing so.
Do you know that before becoming a sage, he was prince Kaushik, born to King Gaadhi. Because of his rivalry with Brahmarshi Vashishth, he performed severe penance to eventually gain the title of Brahmarshi.
He was also the younger brother of Satyavati, mother of Jamdagni rishi and grandmother of Parshuram.