Snakeskin is a person of indeterminate gender who has a tendency to sleep under bridges and in other dangerous places in order to avoid the 'tax' often leveled by human predators and other scum on people of no fixed abode.  Bridges are particularly useful because as well as risking climbing unsteady platforms above the clashing waves of the Thames at high tide, those affected by such things, witches for example, have to cross running water to the nth degree.  Of course, sometimes this means sleeping in the cells held by Thames River Police or even worse, aboard HMS Belfast.

Why Snakeskin?  Well when the Royal Marines decided they didn't want Emem Otieneo (especially when somebody found out that the name 'Emem' means 'Peace') they dropped out and how!  Since they 'shed the skin' of their former existence, they have become someone else, many someones in fact, boys, girls, aliens, robots, whatever people would believe, whatever they wanted to believe.

They have digital footprints of course, one for each 'legend' as they calls them: Hassan the dealer in rare books illicitly acquired; Mimi the hooker; Oko the last resort who stands in the gap between his fellow homeless people and utter destruction... Oko is the one you never want to meet because if you are poor, you only meet him when you are in trouble and if you are rich....  It's not hard to establish identities online.  Much easier than having none.

Physically they are Five Feet ten inches tall, weighing 145 lbs.  Their hair is shaven, is dreadlocks, is blonde, is short.  Their eyes are blue or grey or brown or hazel often behind mirror shades.  Their skin is constant, a shade somewhere between olive and a darker bronze  It could conceivably be a tan.  They could be boy or girl; African or Arab; Mediterranean or even Australian Aborigine.  It all depends on the story they tell.