Who is Ibn Kathir? I know that Ibn Kathir was Shafi'i, so why?

Al-Hafiz Imad al-Din Abu al-Fida: Ismail ibn Umar ibn Kathir, born in Majdal in the year 701 AH. He moved to Damascus with his brother in the year 707 AH after the death of his father. He memorized the Holy Quran and completed its memorization in the year 711 AH. He excelled in Tafsir (Quranic exegesis) and Shafi'i jurisprudence. He memorized the text of "Al-Tanbih" and "Mukhtasar Ibn al-Hajib." He studied under prominent shaykhs and became the son-in-law of Al-Hafiz Al-Mizzi. He had a special relationship with Ibn Taymiyyah and faced trials because of him. He excelled in jurisprudence, Tafsir, and grammar, and presided over many schools, including Dar al-Hadith al-Ashrafiyyah and al-Madrasah al-Salihiyyah. Scholars such as Al-Dhahabi and Ibn Hajar praised him. He has valuable works such as "Al-Bidaya wa al-Nihaya" (The Beginning and the End) and the Tafsir. He was of the Shafi'i madhhab and passed away in the year 774 AH after losing his eyesight in his later years.