use the search function... but lucky for you i'm bored so...
wingless was one of the nick names seraph apparently obtained... so is judas and the prodigal son. one of the theory on it was he used to work for the merovingian. possibly protecting merv from smith (if you recall the scene where seraph said "i have beaten you before..." to smith in revolutions). after some time, he consulted with the oracle and decided that he wanted to be of her service, not the merovingian's... hence the name wingless (fallen angel), judas and the prodigal child.
maybe jedi has a better explanation...
well...we are not exactly sure how Seraph came to be, or what his backstory is, however, based on his nomenclature, we can make a rough guesstimate.
He is called 'Wingless', 'the prodigal son', and 'judas', all references in some form or fashion to judeo-christianity. Judas refers to the Apostle, Judas Iscariot, who betrayed Jesus to the Romans for 30 pieces of silver. The prodigal son was a parable spoken by Jesus in Luke 15:11-32, concerning a son that had run away and squandered his half of his fathers fortune, then returns home destitute. Wingless refers to fallen angels who have lost their wings when they lost grace, or can refer to angels in human form. Taking these together, Seraph would be a turncoat, a deserter, that left the Mervs company, and has now returned, even if not to join up with the Merv again. Even though Seraph and Smith have fought before, i do not think Seraph protected the Merv. We are told that Seraph was saved, more or less, by the Oracle, which is why he is her "Guardian angel" now. This may also be the reason that the Merovingian wishes to harm the Oracle; she took away from him his best bodyguard, one that never loses.
anyway, thats my 2 pence.
well, seraphim are the highest order of the angels...so to call him wingless and judas would imply that he was very high on a power level and made a betrayal evil enough to have his status taken away from him...and as jedi speaks of the prodical son...the son returns to his master (merovingian) but not in the same context as in the bible...