Sarah Ashley (Earth-120986)

Early Life
Marrow was born under strange circumstances. Both of her parents felt unprepared to take the role of parenthood, so they decided to put her for adoption. She was seemingly normal since her birth, but she wasn't very social with the other boys, instead focusing on her art, since she dreamed of being a sculptor. She spent very year waiting for some family to adopt her but as the years passed by, now one would pick her up.

Powers Manifest
In her frustration, she verbally lashed the orphanage's director when she announced that orphans over 15 years old would be released to the street. Refusing to being abandoned she confronted the director, but in the middle of the argument, she released two sharp bone claws from her wrists impaling the director in the eyes of the remaining childern and staff members of the orphanage, revealing her status as a mutant.

Joining the MorLox
Shocked about what happened she ran away from the orphanage, suffering the fate she was going to endure: Live in the streets. She spent her teenage years as a mugger, while developing her mutant powers to intimidate her potential victims, until she was discovered by a gang of thieves and burglars who call themselves "The MorLox", stealing larger targets for bigger profits. She spent years with the gang while she kept working on her powers, managing to control the bones that protude from her body and mantain her human appearance, but releasing them during their raids as "part of her outfit".

Duel between the MorLox and the X-Men
During a major raid on an armored truck, one of the members killed a guard, making Marrow shocked since they never killed anybody, however, she finds out that the whole gang was planning on this since they discovered that she's a mutant and they refuse to have a "freak" in their team. She tried to assault their leader Callista, but she assaulted her with a stun gun, now considering that for her defiance, instead of leaving her there, they'll kill her and make the scene a murder/suicide scenario, however before they could attack her, a lightning storm emerged on the site, impressing the gang who suddendly got attacked one by one by energy blasts, ice blasts and even severe headaches and sudden mists. After the mist was dissipated only Callista and Marrow were left standing, revealing the attackers as Xavier's team.

Joining the X-Men
Callista was fearing a punishment while watching the rest of the gang knocked down but before she could escape, Marrow impaled her on the shoulder so she couldn't leave her team. With the police sirens sounding in the distance, Xavier's team escapes and take Marrow with them so she can talk to Xavier. Xavier explains that he was watching her for all these years and apologizes to her for taking so long to talk to her, promising to help her reach her potential. Marrow seems confused, but seeing the good intentions of Xavier and the support of the rest of the team, she accepts his proposal, finally finding the family she never had. She adopts the codename "Marrow" for battle and as for the civilian identity, she takes on the name "Sarah Ashley", from a pile of random names thrown by Jean