His deed name is 'Travel and Behold', but he goes by 'Come and See.'
"I heard the voice of the fourth beast say, Come and See, I beheld a pale horse: and his name that sat on him was Death" - Revelations, Chapter 6, V7
History
Marcus is an American, and before he became a Ronin he was nominally a member of the Sept of the Green out of Central Park.
Marcus had his first change late in life, mostly due to latent psychopathic traits making emotional extremes unlikely.
He was already heavily involved in organised crime at the time that this occurred, and his life barely changed as he entered the Nation. He had already been taking skills he had learned in the US Military and applying them to the streets for the benefit of the New York Crime Families - Instead he now targets enemies of the Nation and of Gaia.
Ostensibly, Marcus was made Ronin for undertaking an unsanctioned operation against the local Sabbat - disavowed by his Alpha, Kleon Winston, he has lost access to the vast majority of his hoarded wealth and network of criminal contacts.
Personality
Marcus is a Glasswalker's glasswalker - heavily cybernetically augmented, it would not be unfair to describe him as being very close to falling to the Weaver. It's not how he sees it, of course. To him, the Weaver is the balancing force between Wyld and Wyrm, and it is only by working with her that the destructive energy of the Wyrm can be brought to heel.
As such, he has little patience for the prevarication of Theurges and the ephemeral nature of most spirits - the spirits of technology and electricity, the world wide web, these are binary creatures and ones he understands. This has put him at odds with the Theurge of his pack, Melissa, who is the single least binary individual he has ever met. It is this conflict which has lead him to back Skye as the alpha of the pack - he knows he cannot lead the group given the conflict, and he trusts Skye to lead in a way that allows him to do his best work.