False Leo Diogenes II appeared ten or twenty years later after the arrest and possible execution of the Pseudo-Leo Diogenes I. A new impostor appeared in Russia, where the princely chronicles call him "Tsarevich Leon Devgenich", pretending to be Leo Diogenes who had been killed in 1087  .
The Grand Prince of Kiev Vladimir Monomakh, who occupied the throne of Kiev, recognized the impostor as the real son of Byzantine emperor Romanos Diogenes, married his own daughter Maritsa Vladimirovna) and, moreover, decided to support his claims if not by the Byzantine throne, then to a number of Byzantine cities on the Danube, where he intended to create a dependent from Kiev, state education under the nominal superiority of the Lediogen II .
According to the chronicles, “Devgenich” and Maritsa Vladimirovna had a son Vasilko Leonovich who died in the Battle of the Supoy River (1135) near Pereyaslavl. Vladimir Monomonakh selected the city of Voin, part of the Principality of Pereyaslavl for his daughter and her husband. During the excavations at the site of this city, a breast cross was found with an inscription in Greek: "Lord, help your servant Leon." It is assumed that it could have belonged to Pseudo-Leo Diogenes II..
In 1116, Vladimir Monomakh, under the pretext of returning the throne to the "legitimate" Tsarevich, was undertaking a campaign against emperor Alexios Komnenos of Byzantium. With the support of Vladimir Monomakh, Pseudo-Leo Diogenes II managed to seize many Danube cities, including Dorostol, which apparently became the temporary residence of the impostor. However, the "prince" did not succeed in establishing himself on the Danube. On 15 August 1116, Pseudo-Leo Diogenes II was killed in Dorostol by two hired assassins sent to him by the emperor Alexios.
After the impostor's death, Vladimir Monomakh did not stop the war on the Danube, now acting in the interests of Pseudo-Leo Diogenes II's son, prince Vasilko Leonovich. In the same year of 1116, he sent his governors to the Danube, whom he installalled in cities conquered by Pseudo-Leo Diogenes II. The emperor Alexios, however, managed to squeeze out the Russian troops from the Danube valley and occuy Dorostol. Peace with Byzantium was established only after the death of Emperor Alexios and the accession to the throne of his son Ioannes II Komnenos  .
|Offspring of False Leo Diogenes II and Maritsa Vladimirovna (c1085-1146)|
|Vasilko Leonovich (c1105-1135)||1105||8 August 1135|