Matthias was a Christian soldier that was sent to convert the Vikings. On one of the raids he saw a woman who he wanted for himself. The woman was Marion. In time Marion accepted her new home and bore a daughter to Matthias, she named her Hope. But when she tried to flee from Matthias along with Hope, Matthias killed her. Then he bound her soul to him, to be used as a gateway between realms. Soon after that Matthias started with his unholy quest to reach hell. He recruited men every year and lead them to their death, he then collected their souls and offered them to demons. He also brought infected rodents to his hometown and spread the plague, thus getting his hands on souls he couldn't recruit to army. On one night, the people rose against him, and on the same time his daughter Hope saw him opening a gate to hell. Matthias was killed in front of his daughter, but he laughed in his killers face and revealed that they have only helped him in his goal.
Now in hell; Matthias took control of the army he bought himself with stolen souls. His daughter who had renounced her humanity as well, was brought before him, but he cast her out of the window. He then marched against Lucifer and seemingly won, but really he lost, Lucifer took his face and played a game with his subjects. Hope, now named Lady Death revealed his charade and destroyed his father as he was released from Lucifer. Matthias however did not die, he lived on in the ground of Endless Graveyard. One time Lady Death was turned into Lady Demon, Matthias took the opportunity to use illusions to trick Lady Demon on releasing him, but failed. He also fought Cremator when Lady Death was absent from hell, but again he failed to get his revenge. When Lady Death was turned back to Hope by Leviatha, Matthias took the opportunity to convince his daughter to renounce her soul as well her humanity. He was interrupted by Michael who banished his elemental form. Next move from Matthias was to convince Cremator to abandon Lady Death, but he again failed. When Lady Death learns that Matthias has a place in her Endless Graveyards, she sought up the mausoleum. Lady Death then hurls Matthias and her sword Nightmare into the void left from hell, when it disappeared.
But Matthias lived yet again, he awoke in Transdaemoniium, he picked up the sword Nightmare and lived there as he could. His peace was interrupted by the last survivors of Asgard; Vandala, her friends, and Purgatori who followed them. Matthias tried to strike down Purgatori, but she had unimaginable power, and turned him back to human. Purgatori then took Nightmare and left him live in Transdaemoniium.
In ADV Films Lady Death movie, his role is is similar to how he's depicted in the first part of the comic titled The Reckoning. However the one thing that seperates him from his comic counterpart is that he's actually Lucifer.