Steven A. Starphase (スティーブン・Ａ・スターフェイズ, Sutībun A Sutāfeizu) full name Steven Alan Starphase is Libra's second-in-command. A shady man with many connections.
A tall man with short black hair and a thin scar running down the left side of his face. He typically wears a dark grey suit, blue shirt and a yellow tie. His shoes are customed to use his blood-skills, with a pointed metal-like cross on the right, multiple small square crosses on the left, similar to the cross on Klaus' knuckle. 
Seemingly laid back, he gives off an air of a suave businessman, always with a quip or sardonic comment to make about the situation. When crossed, however, he shows a ruthless side, and is not above using his connections to make 'problems' disappear.
Follow That Phantom Ghost Wagon.
Steven is first seen discussing the situation of Leo's kidnapping and Zapp's hospitalization with Klaus. Initially overwhelmed by his leader's fierce expression, he realizes Klaus has been worrying himself sick and speculates he has a dozen ulcers from nerves.
After attempting to put the man at ease, he receives a report from the hospital and realizes Zapp tagged the wagon that took Leo and has been extending the thread with blood.
Instructing Chain to pursue, he and Klaus pile into Gilbert's car and take off down the street, Steven casually flipping passing drivers off before urging Klaus to destroy the crashed wagon.
A Game Between worlds.
Steven is first seen inquiring of Gilbert as to why Leo is sleeping in Klaus' office, commenting on the boy's naiveté at refusing additional pay due to 'not wanting special treatment'.
When Zapp comes in, covered in blood from a struggie, he brings up the existence of the drug Angel Scale and mentions the two monomaniacal Gatekeepers responsible for screening the gates.
Following the news report detailing the Attack on the U.S President, Steven is among those intimidated by Klaus' expression, only to react humorously when it's revealed he was playing Prosfair.
During a Libra Party, Steven is seen as part of a 'Cabal', chatting amiably with Klaus and several other Libra members, during which time K.K vocally announces her distrust for him, calling him scarface.
When Leo unwittingly reveals he saw the Aura of a Blood Breed in the Subway, putting everyone on edge, Steven pulls out a color coded sheet to confirm the color of said Aura. He is later deployed along with K.K, to the latter's ire, and manages to defeat her ghouls before being soundly beaten by the vampires.
As the Elder mocks them for trying to use blood correctly, Steven stalls for time by implying that the ones with the fangs to reach them will arrive shortly, allowing Klaus to come up behind them, crush Antonio and seal the Elder with his pattern 999.
Day in Day Out
Steven is seen in his apartment planning a house party with the help of his housekeeper Veded. He begins to receive calls from various friends of his, either enquiring about the party or what party favours they should bring.
Later in the day, Steven's guests begin to arrive. Happy with the preparations, Steven sends Veded home early and thanks her for a roast she made for the party. Steven then welcomes two more guests in via the front door but falls as he does so, catching his leg. He brushes himself off and returns to the party. Later after the party has progressed some, a party-goer signals that they are out of booze. As Steven goes into the hall to fetch some more, all of the guests turn in unison and reveal Biological Augmentations. Steven does not seem surprised but is instead rather put out that two of the guests "Larry" & "Ellen" knew each other despite him introducing them to each other earlier that day. As Ellen mocks him and warns him not to make a single movement, Steven tells his guests that he is happy that the roast made by Veded won't be ruined. Steven then explains that his attack had already taken place at the front door. As he tripped, Steven released tiny strands of blood in the form of his Aguja del Cero Absoluto an attack that freezes a person solid by entering their bloodstream. The assassins are all frozen in place, with Steven explaining that they almost succeeded but small changes in the weight and smell of some of Larry and Ellen tipped him off. Large ominous figures then appear behind Steven. Ellen believes the figures to be members of Libra but Steven explains that his "Boss" would never allow the cruel fate that is to happen to them.
Steven then leaves the room to talk to the individual in charge of the operation before leaving his apartment for some fresh air, wearing a melancholic smile. While outside, Steven reminiscences about Ellen, before remarking that he was having "Too much fun" Veded drives by and stops when she sees Steven. revealing that she is travelling home with her two children and a stray cat that the two children found. Veled asks if the party is over already and Steven confirms that it is. Steven says hello to the two children and pets the cat, unaware that it is the same cat that Leo and Zapp are frantically searching for. Steven tells Veded that her two children are nice. The group is then interrupted as Leo and Zapp ride by with Steven remarking happily that a lot of his friends are out tonight.
Power and Abilities
Esmeralda Blood Freeze (エスメラルダ式血凍道 Esumeraruda-shiki Kettōdō?): Steven's ability allows him to decrease the temperature of his blood in order to freeze targets. His techniques are spoken in Spanish. This is called Esmeralda Blood Freeze Style in the FUNimation dub
- Avión del Cero Absoluto (絶対零度の地平 Avion deru Sero Abusorūto?, literally "Plane of Absolute Zero"): Steven stands firm and freezes the entire ground.
- Lanza del Cero Absoluto (絶対零度の槍 Ransa deru Sero Abusorūto?, literally "Lance of Absolute Zero"): A long-ranged based attack that Steven either summons or launches spears of ice.
- Escudo del Cero Absoluto (絶対零度の盾 Esukūdo deru Sero Abusorūto?, literally "Shield of Absolute Zero"): Steven summons a giant block of ice which he uses as a shield or barrier.
- Viento del Cero Absoluto (絶対零度の風 Viento deru Sero Abusorūto?, literally "Wind of Absolute Zero"): Steven use wind blow and he pulls out the wind-borne particles of blood and freezes the wind-blown enemy.
- Aguja del Cero Absoluto (絶対零度の小針 Aguha deru Sero Abusorūto?, literally "Needles of Absolute Zero"): Steven uses droplets of blood to form into needle-like objects to pierce into his opponent's skin and freezes them from the inside-out. This technique is particularly subtle and the target may very well not notice Steven's blood entering them until he freezes them, sometimes several hours later.
- Espada del Cero Absoluto (絶対零度の剣 Esupada deru Sero Abusorūto?, literally "Blade of Absolute Zero"): Steven turns blood into an ice blades and then targets his enemies in a row strike until the enemy is ripped apart by the ice blades. Ice blades thrust into the enemy to knock out a few moments.
- The Blood Blockade Battlefront Official Fan Book B5 reveals Steven's height to be 182 cm (5'11'' and 3/4, almost 6"0) and weight to be 69 kg (152 lbs).
- The Blood Blockade Battlefront Official Fan Book B5 also reveals Steven's middle name to be Alan (アラン), which is inspired by the famous French actor Alain Delon.
- In a mini-comic by Yasuhiro Nightow that was included in the volume 1 DVD, Steven and K.K. are revealed to be in their 30s.
- In a Q&A session with Nightow, it is revealed that the red marks on the back of Steven's neck are from a tattoo that runs from Steven's neck, down his back, and reaches all the way to his foot. The tattoo design itself is still in the works.
- The names of his attacks imply he is of Spanish or Hispanic heritage.
- It is also stated that he and Klaus know about 9 languages total.