Seventeen years ago I was writing posts over at my old site Mahdiwatch about an Iraqi Shi`i Mahdist movement centered around one Ahmad al-Yamani. I even interviewed him virtually at one point, although I have since lost the notes. As near as I could ascertain, al-Yamani was claiming to be a representative, or herald, of the coming 12th Imam al-Mahdi–sort of a John the Baptist figure, mutatis mutandis. He also said that his movement was peaceful, although even then the Iraqi government alleged his followers were actually violent.

His Ansar al-Mahdi had not been heard from much in the intervening years. But two days ago, Shafaq News (an Iraqi, pro-Kurdish site) reported that Ahmad bin Hasan al-Yamani, “a senior leader of the Al-Yamani Movement in Najaf province” had been arrested. He was described as “the chief strategist behind the group, which has called for attacks on top religious figures.” Al-Yamani “had evaded capture for years.” The article went on to state, confusingly, that al-Yamani had claimed BOTH to be the “deputy of the Mahdi” AND “the first of twelve Mahdis who follow the twelve Imams.”

In mainstream Twelver Shi`ism "al-Yamani" (the Yemeni) is indeed an eschatology-adjacent figure who comes from Yemen and prepares Muslims for the arrival of the actual Mahdi, the End Times leader who will, along with the returned Muslim Jesus, bring the whole world under the sway of Islam. (This bit in the article about 12 Mahdis makes no sense. In Twelver Shi`ism, the the 12 Imams are descendants of Muhammad through Ali’s line, the final one of which will be the eschatological Mahdi. There are not 12 Mahdis in this branch of Islam.)

Mahdism has been a hugely potent strain in the world’s second-largest religion for over a millennium, as I outlined in this article (and in several of my books). Men claiming to be the Mahdi are often a thorn in the side of established rulers–as al-Yamani appears to be for Baghdad. Perhaps his followers were violent; or the Iraqi government simply needed to put him away, as a political and religious irritant, and ginned up accounts of planned assassinations. But arresting such figures is usually insufficient to stop their movements, as the Mahdist imperative is deeply embedded in both Shi`i and Sunni Islam and serves as a powerful tool for combating perceived unjust rulers.

Imam Mahdi and Signs of the Appearance: one of my many Arabic books on this topic.