Abdullah ibn Abi Umayyah RA of the Banu Makhzum was the Prophet ﷺ's first cousin through his aunt Atikah bint Abd al-Muttalib and the half-brother of Umm Salamah RA. Though he grew up with the Prophet ﷺ, he was one of his sharpest opponents in Makkah, swearing he would not believe even if he saw him climb into the sky and bring down a book, a demand the Qur'an echoes [17:90-93]. With Abu Jahl he urged the dying Abu Talib not to abandon the religion of Abd al-Muttalib. In 8 AH he and Abu Sufyan ibn al-Harith came out to seek the Prophet ﷺ's forgiveness before the Conquest, were at first refused, and then became Muslims.
All 3 events
First cousin through his mother Atikah bint Abdul Muttalib, the Prophet ﷺ's paternal aunt. Interjected alongside Abu Jahal to stop Abu Talib from saying the kalimah on his deathbed