Though, it's good to note that Lizzie is a member of the Middleford family, known for their exceptional swordsmanship.
What really seals the deal is how she addresses the zombies. She states proudly that she's not only gonna be Ciel's wife, but she also states how she will be the wife of the Queen's Watchdog. THAT'S amazing.
I also recommend the servants when the Circus tried to invade the mansion. Ciel didn't necessarily hire them for cleaning the house; he hired them to take care of intruders while he's away. Mey-rin is a sniper with great accuracy, Finn can throw heavy marble statues at his opponents, and Bard is as dangerous with a gun as he is with a flamethrower. Add them together and you get some WAY badass fighting scenes with these three.
The start of that sequence really sells it. Jumbo has apparently bashed Finn's head in, and apologizes to him as he walks off. Then Finn grabs his leg. Meanwhile, Ciel is mocking Joker's proclamation that the Circus never leaves survivors: "What do you take them for? They are servants of the Phantomhive Family." Finn tells him that Ciel told him not to let anyone onto the grounds and punches his head in..
chapter 61 Undertaker vs Ronald, Grell and Sebastian at the same time. Undertaker is winning as of the end of the chapter, with very little apparent effort..
In chapter 64, Undertaker cuts the Campania in two.
Also in chapter 64: Sebastian taking down Ronald despite the fact he can "barely stand up".
Sebastian taking on an entire horde of zombies in a lifeboat while floating in the middle of the frozen Atlantic all while bleeding heavily in chapter 65. He wins, of course but that does not make it any less thrilling or badass.
Chapter 71 for Ciel. To retaliate against Maurice Cole, he confronts him about his lying (from the time to meet at the Swam Gazebo to making others do his chores). Once cornered, Maurice attempts to have his friends rape Ciel, but the heads of the dorm charge in, having overheard everything because Ciel had tapped the room. Maurice is then denounced by Redmond and breaks down. Ciel then offers a tissue to him and says that they can start anew, right before revealing that he spread around pictures of Cole without makeup on because 'to start, everyone should see your true face.' Revenge is a dish best served cold indeed.
Chapter 77 for Edward. To win the cricket tournament's deciding match, Ciel and Sebastian decided to use an orchestra to disguise the use of a particular sound to signal when a pitch hits the ground so the Blue House players can strike it at that exact moment, resulting in them earning 40 points in a row...then Edward steps in. Not only does Edward see through this, but he beats it! Having learned to use the Purple Burnout used by Cheslock through observation alone, he proceeds to consistently bowl out Green House, beating Sebastian's orchestra's swing. Sebastian was shocked that this happened.
Chapter 79 for Lawrence Once it's his turn to fight Edward, he somehow toss a ball up in the air, turns around and walk away. What the audience sees it as a wild ball until THE BALL HITS THE TARGET LIKE A CANNONBALL surprising everyone even Edward.
It's a small one, but, in his introductory episode, Agni the Funny ForeignerBattle Butler actually manages to get a draw in fencing against Sebastian. What is confirmed by Sebastian himself to be nothing more than an ordinary human — not an asura, demon, angel, shinigami or any sort of supernatural being, just a plain vanilla Badass Normal — managed to get a fencing draw against the most powerful demon in the series. And he did this against a Sebastian who was going all out — Ciel directly ordered Sebastian to win, so that means he was fighting with no Power Limiter.