Sharon is a character from the Dimension of Rain and the love interest of alt-Rammer. She was DFA'd out of the dimension for having had contact with Riff when he arrived. She has not been seen outside of her REA-5 armor.
According to Rammer, Sharon used to be a sort of mystic before 4U City rose. However, immediately before the city was created she became obsessed with the web of fate and the fate spiders. On the day 4U City was created she went to Rammer and told him that the web had broken. She was later placed in an REA-5 squad and was present when Riff and Zoë arrived in the dimension. When the squad leader said that they would have to shoot them she voiced the concern that they might be from another dimension. The leader didn't care and fired upon them anyway. Rammer later speculated that it was her voicing her opinion that got her and the rest of the squad judged. She hasn't been seen or heard of since, although her judgment seems to be a major motivating factor behind Rammer's drive for revenge.