"I know 347 ways to snap somebody's neck. 162 of which don't involve the spilling of blood."
Ryu is a rather suave (though somewhat rude at times), and sociable young man. A womanizer, he will constantly flirt with anybody he deems attractive. He is (or at least tries to be) a smooth fast-talker with even quicker fingers. Ryu's a compulsive and incurable kleptomaniac, taking after his father in that aspect. While Ryu may be a bit of a jerk at times, however, is very loyal and will always stand up for his family and those he implicitly trusts. Ironically, Ryu cannot stand authority and will often go out of his way to rebel against or outright antagonize them simply because of his natural rebellious nature.
Ryu is also a self-described combat pragmatist and will take any advantage during a battle, regardless of how cheap or dishonorable it would be. He is also skilled in ninjutsu, infiltration, and assassination techniques as well as how to disarm or bypass security systems of all kinds, magical or otherwise.The young man is also a bit boastful, and is not shy about his skills (despite the fact they aren't exactly the most honorable), and holds an Inigo Montoya-style love for his family, his father in particular. Ryu is also sports a great sense of humor and is constantly joking and throwing out quips from Muggle movies, literature, and certain memes...but he can be deadly serious when he absolutely needs to be.
At least four concealed knives--two in his shoes, along with two serrated knives strapped to his legs/thighs for easy withdrawl that he almost always uses in a fight. He also carries a satchel with whatever tools of the trade he needs for his thievery.
He does carry a cell phone, which is--actually, surprisingly, is his wand transfigured into it--capable of getting reception anywhere in the world and capable of "Speed-Dial Spellcasting" wherein a spell is programmed to a number and only needed to be pressed to be cast without saying the actual incantation.
Ryu Dayclaw, as well as being is Drake Nightwing's cousin through his maternal side of the family (his mother, Amara Dayclaw, is Alicia Nightwing's sister), he is also the son of Rex Dayclaw....a very infamous wizarding thief and burglar who was in the Top Three of the Most Undesirable in the Ministry for being one of the very few to have successfully broke into both Gringotts and the Ministry itself and successfully elude the Aurors--feats only matched by the Golden Trio themselves.
With Rex being a wanted man and still wanting to protect his family, he had been forced to go into hiding among the Muggles down under in Australia where he lived with his wife and young son. Rex and Amara learned very quickly to adapt to Muggle culture. As a result, Ryu has grown up among them almost since birth.
Rex has since enigmatically gone missing since Ryu has been nine (and is presumed dead), but even since Ryu has vocally boasted that he would go on to match--and even surpass--his father's feats by willingly following in his footsteps as the best Master Thief in history. Ryu's skills in burglary is matched by none as his knowledge of circumventing almost all known locks and security make him a true force to be reckoned with. His in-depth knowledge of Muggle culture and history is a value since he has lived among them for almost his whole life (as well as being the son of both a witch and a wizard).
Never actually attending Hogwarts, Ryu has nevertheless seen a great deal of the world throughout his life. Traveling often, far and wide with his mother, Ryu has picked up several a skill...among them being to pilfer, peruse, swipe, snatch, and steal almost anything not bolted down and on fire, martial arts with elements of ninjutsu (though he is not a ninja in any sense of the word), as well as his proud knowledge of "347 ways to snap somebody's neck." He is also very knowledgeable in the field of Ancient Runes, parts of History both Muggle and Wizard, and very skilled in Apparition for quick getaways....and other methods of escape, should he be caught in an Anti-Apparition field.
Most of the elements of his past are unknown, yet distinctly shady. Yet despite this and his...questionable expertise, Ryu would never willingly join anybody dedicated to harming innocent people for the sake of harming or killing innocents. He, in his own words, only steals from people "who deserve to be stolen from".
He was not actually given a letter to join the mission regarding the Department of Magical Law Enforcement...but only joined at Drake's bequest in an effort to help him assist the crew to combat whatever force they're facing. Ryu, always willing to help his family with anything (even if it IS enforcing the law; a concept amusing to a lawbreaker such as him), agreed.