MacDonwald Walters in the second child and youngest son of Natalie Walters and a mutant whose real name is unknown to all of his family, but is referred to as Psionic, an infamous member of the Brotherhood of Mutants. As one can imagine, he did not stay around to help take care of his children, yet was not "unopposed to making more" as Natalie would often say. Natalie struggled to raise her children in New York, yet, having been born into a large family of mutants, she had many connections to many members of the X-men, as well as the Brotherhood, he had help when she needed it and none of the children went without. Growing up, Mac was often cared for and taken care of by his older brother,Ricky,and as he got older, did the same for his younger sister Lily when she was born. Life for them continued on this way until Mac was 14, when Psionic visited their home, offering them both a warning and an invitation, saying that soon a few of Natalie's relatives would come to visit them soon to recruit them to join the X-Men, and that if they joined them, he would not hesitate to kill them if tasked to do so. He then offered to allow them to join the Brotherhood. Just as Mac was about to accept, Natalie drove him away. However, what Natalie didn't realize was that Psionic had taken samples from his children's DNA as a insurance policy. He wanted to ensure that he would have his children on his side one way or another. He had a friend who called himself Pestilence, who had recently created a means of cloning with no real detrimental effects. The only cause for concern was that it could not fully clone the X-gene. If a mutant were to be cloned, the clone would be a mutant, though their abilities may not be the same.
As such, the children were cloned. The clone of Mac being Elias. As a clone, his powers differed from Mac's. Psionic and Pestilence tried their best to bring out the hatred in him, and turn him evil. They soon found, though, that said hatred was not locked within the DNA. Not long before they were going to scrap the project, S.H.I.E.L.D performed a raid on their lab, arrested Psionic, and when they failed to apprehend Pestilence, they took the clones in. From there, Eli was soon taken in and raised by S.H.I.E.L.D.Not long after, unable to deal with the constant use of his powers, several agents sent him to the Xavier Institute, where he then trained and became the X-man known as Zephyr.
Eli is described as being a joker. He's often lacking in seriousness in dire situations. He's also seen as being a slacker, due to his rarely being motivated. He's flirty and charming, having been raised as a gentleman.
Being raised around S.H.I.E.L.D had little effect on his personality, though it did take its toll. He is quick to answer to authority, and is rarely hesitant to follow orders.
Despite his slacker attitude, his training has made him militant and brutal when angry, and is a competent and experienced fighter, in both armed and hand to hand combat.