That is a important event in Sudanese, Egypt, and the muslim world History, indeed i have mixed opinions and conflicted in the Mahdist war, although today he is a national hero. In one end, he has galvanize all the groups in resistance to colonial powers, but on the other he had forced many Christians to convert to islam, however when the British established control in Anglo Egypt Sudan, many Copts reconverted back to Christianity. Also, as i remembered from my personal reading he was a big advocate of slavery of ethnicity further South or South Kordofan near today South Sudan, who Northern individuals business people used to trade these people to North Africa and the Middle East, and they kept a host of slaves themselves, it was a major source of income back then as you know, and today some of the big(rich) families in the north are descendant from people who once practiced that trade, but a few now own major businesses in the country and elsewhere. Actually the actor Alexander Siddig who is half British and Northern Sudanese, and was a actor of "Games and Throne" an his ancestry is from those people, and his Uncle is a major player in Sudanese politics today.
Alexander Siddig - Wikipedia