Full name: Pietro Django Maximoff
Codename: Quicksilver
From: Transia, but recently naturalized to the United States
Appearance: 6'0", 175 lbs, Blue eyes and Silver hair. In costume, he wears a silver/blue suit with white lightning bolts down his legs and across his chest. Rarely is out of costume, due to the high speeds ripping off clothes that aren't designed for high winds. But, when out of costume, he wears tight fitting stylish clothes that are available to the region.
Powers: Extreme supersonic speed in both mind and body, even capable of running across large expanses of water. He resists the effects of friction, has a reduced need for oxygen, and resists kinetic impact while moving at super-speeds. Has superhuman strength (Can lift about a 1/2 ton), and Enhanced Durability. Has yet to develop traveling through time or restoring the lost abilities of mutants, if he ever will in this reimagination of this canon character. 
Pros: Other than his speed, he has been trained in Hand-to-Hand combat by Captain America. He also speaks Russian, Romanian, English, German, Spanish, French, Italian, Japanese, Mandarin, Cantonese, and Korean.
Cons: MUST consume 4-6000 calories a day due to the high output of his body. Appears to have inherited his father's propensity for mental illness and depression. Pietro has undergone mental breakdowns, episodes of mental illness, and severe depression.
Brief bio: Pietro and his twin sister, Wanda, were raised by Django and Marya Maximoff, a gypsy couple. As adolescents Pietro and his sister Wanda discovered that they had peculiar talents. When Django began to steal food to feed his starving family, enraged villagers attacked the gypsy camp. Using his phenomenal speed, Pietro fled from the camp with his sister. Over the next few years, Wanda and Pietro wandered central Europe, living off the land. One day, Wanda accidentally caused a house to burst into flames with her uncontrollable hex powers and the pair was chased by superstitious townspeople. Despite Pietro's attempt to defend her, the twins were soon overpowered and were rescued by Magneto. Unwilling, but believing they owed him a debt, the twins became members of Magneto's Brotherhood of Evil Mutants as Quicksilver and the Scarlet Witch. For months they served under Magneto. When the extraterrestrial Stranger transported Magneto from Earth, the siblings had nowhere else to go. They learned the Avengers and S.H.I.E.L.D. were seeking new members, so Quicksilver attempted to convince his sister to leave for America and join the hero team, but she wanted to stay. The divergence that Quicksilver felt still made him want to leave, but he won't allow anyone to harm his sister. So, he left his sister behind. Alongside Captain America and Hawkeye, he remained with the teams for a while. This is where he currently lies in his life. He does not appear to know the current whereabouts of Magneto, be he is aware that Magneto is his father. He has mixed feelings on the subject. He is extremely protective of his sister, Scarlet Witch. Mess with her and you won't see him coming.
He perceives everyone as moving in slow motion, so he may tend to get impatient from time to time. He has been quoted by saying, "Have you ever had a day where you are at the ATM and you are in a hurry because you're running late but the person in front of you doesn't know how to use the ATM and they're taking forever? Now imagine what it must be like to spend every day surrounded by people who don't know how to use the ATM."

Bio has been slightly modified.