Ace first met Levi when he was sneeking back into his home, when they collided with each other in one of the hallways of the Chiyoru mansion. The fact that she refers to him as "Master" rather than Levi. During their first encounter she lost her temper and snapped at him for not watching where he was going, only to look up and realise then who he was. When he didn't reply to her she started blushing and panicking, trying to wipe her lipstick off of his clothes and apologising for getting him messy, before turning on her heel and dashing away, embarrassed. She later developed feelings for him, feelings that remained, for the most part, unrequited. She loved him, but found him unapproachable, and didn't know how to talk to him because she was to shy, but his best friend Jack helps her talk to him. For a while she even envied Jack, and resented him because he was close to Levi ways she never could be, but in time she grew to accept it, and was content to just see Levi happy, even though he was only truely happy around Lacie.
"...even so, because Master Levi smiled... that is enough."
Lacy thought Levi made a pocket watch for her but in reality it was made for the Lacie he truely loved. She took the pocket watch without asking and he didn't know. Levi became panicky and asked if she has seen it and she said she took it, him accusing her for stealing it. Soon telling her it wasn't hers. She apologies, feeling lose of hope that they would be together but soon Levi's mother engaged both of them. He broke it off when he found Lacie.
Jack had first met Lacy at the Chiyoru mansion, where he would sneak in through secret passageways to meet with Levi, his best friend. He would often tease her and shortened her name from Lacy to the nickname 'Ace' (because Levi asked him to find a nickname for her) and would often ask her opinion about his latest works (paintings). He infuriated her but she would still like him, because he made Levi smile. When she learned that he had betrayed Levi Chiyoru however, they were no longer on friendly terms and she was quite eager to find him to understand why he would do such a thing to his supposed best friend.
Ace went to go search for Lacie to threaten her to say away from her man and to understand what was so great about her. Soon meeting her, threatening her calling her "red eyed freak," but in a responce Levi refused ro talk to her and called her "Good fro nothing." Making her even more angry at Lacie, in a resolt, Ace pulled her hair and pulled out her dagger on her but that didn't end the way Ace wanted it to. Lacie took the sharp part of the dagger and pulled it to her throat. Telling Ace to cut her throat but she didn't. Later on when Ace watch stalking Levi and Lacie out on what Ace thought was a date and when Lacie and Levi went there seperet ways, Ace took the change a stabed her in the stumack area and cut her on her left arm.
When Ace pulled out a dagger of Lacie, Celia wanted to kill Ace/Lacy. Ace and Celia have no friendly relationship.