Dmitri Utkin, a longtime lieutenant to the Russian mercenary chief Yevgeny V. Prigozhin and the person whose nom de guerre impressed the title of their personal army outfit, Wagner, was extensively believed to have died along with him in a plane crash in Russia on Wednesday. He was 53.

Mr. Utkin’s demise has not been formally confirmed by the Russian authorities or by Wagner, however he was listed as a passenger on a aircraft that went down in a discipline because it was flying to St. Petersburg from Moscow.

Mr. Utkin, a veteran Russian army officer, was carefully intertwined with Wagner from its emergence as a reasonably modest combating group a decade in the past to its evolution right into a brutal, armed-to-the-teeth pressure keen to do the Kremlin’s bidding from Africa to the Middle East to, most lately, the most popular spots on the Ukrainian battlefield.

But his precise function was a bit murky.

Over the years, Mr. Utkin was at instances known as the “founder” of Wagner, which first got here to public consideration throughout early forays towards Ukraine ordered by President Vladimir V. Putin in 2014, a precursor to the full-scale invasion of 2022. Wagner mercenaries fought alongside pro-Russian separatists within the Donbas area, commanded by Mr. Utkin.

Whether he was the group’s precise founder, although, turned much less and fewer sure over time. “While Dmitry Utkin has been widely presented as the front man and ‘principal’ for the Wagner PMC, there is ample data suggesting that his role was more of a field commander,” a report issued in 2020 by the investigative web site Bellingcat mentioned. Open-source information, the report mentioned, strongly prompt that Mr. Utkin was “not in the driver’s seat of setting up this private army” however reasonably was a “hired gun.”

Part of the problem in understanding his function was that whereas Mr. Prigozhin was outspoken of late, delighting in seizing the highlight and denouncing rivals within the Russian common army, Mr. Utkin was hardly ever seen in public. Bellingcat referred to as him “camera shy.”

In many respects, although, his affect on the tradition of Wagner appeared clear.

Mr. Utkin, a retired Russian Special Forces officer, was described as fascinated by Nazi historical past. The mercenary group’s title — and, earlier than that, Mr. Utkin’s army name signal — was mentioned to have been inspired by the composer Richard Wagner, a favourite of Hitler’s. Some of the group’s fighters appeared to share that ideology: Ancient Norse symbols favored by white supremacists have been photographed on Wagner equipment in Africa and the Middle East.

Mr. Utkin, who was born in 1970, served with the army in two wars in Russia’s restive Chechnya area and was within the G.R.U., the Russian army intelligence company, till 2013, in accordance with a 2020 report from the Center for Strategic and International Studies. After that, the report mentioned, he commanded a Spetsnaz particular forces unit and attained the rank of lieutenant colonel.

But it was as a part of Wagner that he attained notoriety.

In 2015, a 12 months after serving to shear off sections of jap Ukraine, the Wagner group turned its consideration to Syria, tasked by the Kremlin not solely with bolstering President Bashar al-Assad within the nation’s civil struggle but in addition with seizing oil and fuel fields, American officials have said. Wagner operatives have additionally fought in Sudan, the Central African Republic, Mali and Mozambique, extending Russian affect in Africa by proxy.

Officially, the Kremlin denied ties to Wagner, however in 2016 Mr. Putin awarded Mr. Utkin army honors at a banquet.

A 12 months later, the United States bestowed its personal recognition of kinds: It imposed sanctions on Mr. Utkin over his actions with Wagner — particularly, recruiting soldiers to affix separatist forces in Ukraine. (Britain, the European Union and Canada also imposed sanctions on Mr. Utkin and Mr. Prigozhin.)

In 2022, after Russia’s full-scale invasion of Ukraine started, Wagner’s fighters took on a significant function, most notably within the bloody, almost yearlong battle for Bakhmut, the place Mr. Prigozhin’s mercenaries finally claimed victory.

But the glory was fleeting.

Mr. Prigozhin grew more and more incensed at what he referred to as the incompetence of Russian army leaders, and whereas he was cautious to profess loyalty to Mr. Putin, he spared no phrases in his denunciations of the president’s underlings. In late June, phrases turned to motion, and Wagner forces briefly took up arms towards Russian troopers, outraging the Russian president.

Inside and out of doors the nation, many watched carefully to see what destiny may befall Mr. Prigozhin.

In the times that adopted, Mr. Utkin stayed by the Wagner chief’s aspect. And the following month, video emerged that appeared to point out Mr. Prigozhin delivering a speech to Wagner fighters who had relocated to Belarus. After ending, he turned the ground over to Mr. Utkin, who this time didn’t keep his customary discretion.

“This is not the end,” Mr. Utkin mentioned.