In Blood Omen 2, Marcus was one of the vampires acting under the command of the Sarafan Lord. Kain encountered him in the Upper City area of Meridian. The two were not on good terms, even before Marcus allied with the Sarafan. Some time before Kain's defeat by the Sarafan Lord, he had tried to murder Marcus, apparently attempting the act personally. Marcus escaped with his life and laid low. He joined with the Sarafan when their army triumphed over Kain's.
Marcus believed Kain had attacked him that time because Kain considered him a threat, fearing his growing powers. Marcus was confident in his skills, and particularly proud of a Dark Gift he possessed: 'Charm'. He attempted to use this gift against Kain, to rob him of his free will, but it failed. However, as a side effect, he managed to glimpse Kain's thoughts. Marcus learned of his intention to find the Bishop of Meridian.
Kain was drawn into a race against Marcus to see who could find the Bishop first. Marcus had more success using his Dark Gift on the robed humans from the cathedral. He controlled their minds and directed them to fight against Kain. Marcus was known by the Upper City's Sarafan, and he enlisted their co-operation too, without needing to resort to psychic coercion. When Kain finally reached the Bishop, he found that Marcus had indeed beaten him, and the old man was under the other vampire's control.
Kain chased Marcus as he ran from the scene; he had to kill Marcus in order to free the Bishop from his influence. They fell through the glass ceiling of the cathedral when it could not support their combined weight, and fought inside the impressive building. During the fight, Marcus employed another of his abilities - invisibility - and also summoned more robed humans to aid him. Kain defeated him anyway, and by 'absorbing his veins', Kain drew the Dark Gift 'Charm' from Marcus' body after it came to rest on the altar.
Like the vampires of Soul Reaver, Marcus appeared to have a weakness to sound, or conversely, like Turel in Defiance, his hearing may have been enhanced and therefore exceptionally sensitive. He was forced to cover his ears when Kain rang the cathedral bells during their battle, but the same noise didn't bother Kain in the slightest. Also, it was unknown if his invisibility was a Dark Gift in its own right, or just an extension of his psychic powers; it was possible that he removed himself from Kain's vision through mental manipulation. Whatever, the ability to make himself invisible - through any means - was a useful skill to have. It was not entirely surprising that Vorador had tried - many times - to persuade Marcus to join the Cabal.