Ace is an character in Alice in the Country of Hearts franchise. His job is to kill people and collect their clocks for Julius the clock repairer.
His role in the game is act as a knight that serves Queen Vivaldi. He hoped that by meeting Alice, the outsider who made someone like Julius more open, would help him change as well. Unfortunately, when he noticed no change, he wondered what would happen if he killed Alice. However, he changed his mind when she said that he didn't need to change because he seemed like the kind of person that was happy no matter where he ended up. That, and he wanted to listen to her heart again. He also serves Julius, the undertaker, who fixes clocks (hearts of the inhabitants) and supplies Julius with clocks by massacring citizens of wonderland who try to destroy their clocks.
He is created by Quin Rose and illustrated by Soumei Hoshino. Although the author has not mentioned any inspirations used to create him, Ace is not based on a character from Lewis Carrol's novel, Alice in Wonderland. Only his name is based on the Knave of Hearts.
He gets lost easily and does not care if it offends other male characters. Evidence of this is when Elliot March points a gun at him for stupidly wandering into Hatter territory with Alice, and Ace acts cute and ignorant claiming that he didn't mean to. Ace is rather...unstable at times. Usually, he appears like a blissfully ignorant and optimistic fool strolling all over the country with no idea where he should be, but at other times, he exhibits a darker and even less caring side. He blatantly states that life has little to no worth in the Country of Hearts and has no problem with killing people who get in his way to make his point.
On another note, it has been shown in the manga that Ace can hold his liquor fairly well, drinking it nonchalantly throughout the ball he attends, unlike Julius.
He wears a red coat that is fitting for someone of a Knight's role. When he works for Julius, he wears a cloak over his red coat and a masquerade-like mask.
He meets Alice after coming out of a bush. He leads Alice back to the Hatter's mansion where he gets into a fight with Elliot who is angry at Ace for coming back lost. Blood stops their battle.
He's an expert swordsmen as he demonstrates by blocking a gun shot. He can change objects into a sword or a gun.
Ace is a character from a visual novel, Alice in the Country of Hearts. This is before the anime adaptation.
Alice in the Country of Hearts: Wonderful Wonder World
This is the movie based on the Alice in the Country of Hearts otome games.