Later, she was seen with the other Simon Famiglia members and Vongola Guardians in a restaurant, discussing about a group to protect Tsuna in each area. Kouyou is against this and almost starts a fight, but Adelheid easily made him silent with just one word. She then said she would talk to the remaining members about it. This makes Gokudera think that she was the leader of the Simon Famiglia. Before arrangements could be made, Adelheid comments that she would like to talk with other members who weren't there and give it some time to think.
At the Simon Famiglia hideout, Adelheid discussed with the other members on how to protect the Vongola Famiglia, but in their own way. Everyone agreed with the idea, except for Julie, who didn't feel too well. Adelheid then asks Enma's opinion on the idea, but he responds that he didn't really care. Adelheid also asks everyone if they have been taking good care of "that" and asked Enma to show them the Ring that proved that he had the inheritance to be the next Boss of the Simon Famiglia.
She then later told Tsuna that they would guard him while eating breakfast at his house along with Large Ooyama and Kouyou. Each of them would stay in his house to guard him.
A few days later, it was Shitt P! and Gokudera's turn to guard Tsuna, but it went nowhere because no one understands what Shitt P! is doing. Gokudera is forced to go after Shitt P! when he sees Adelheid. Gokudera became suspicious that she was alone, but she responded that she was taking a walk. She then asked Gokudera if he was getting along with Shitt P!, but he responded by saying that he couldn't understand her. She later gave him hints on how to communicate with her by telling him that Shitt P! had been sending him signals from the beginning.
The day after that, it was Enma's turn to guard Tsuna. After Tsuna and Enma talked, he called Adelheid and said he really thought that Tsuna wasn't a bad guy. She reminded him not to forget the "Sin of Vongola." Adelheid told him if he is certain, he should test Tsuna first without the other members knowing. The next day, Adelheid saw Tsuna at school with his friends, unaware of Enma's test. Adelheid later found Enma sitting alone in the factory and said that Tsuna went to school and ignored the letter he wrote. She then stated that these were the Vongola's true colors and that they had no reason to change their plans. Adelheid told Enma that they would make the Vongola Inheritance Ceremony a success and that it was the only way to restore the Simon Famiglia's power.
Later that day, Adelheid and the rest of the Simon Famiglia were seen at the hospital with the rest of the Vongola Guardians to hear about Yamamoto's condition after he was attacked in the baseball locker room by Kaoru Mizuno. Adelheid stated that the culprit that was strong enough to take down a Vongola Guardian was most likely the same person who attacked the Giegue Famiglia. Kouyou also told them that they had no leads, but was interrupted by Reborn, who said that he had found a lead. This news surprised the Simon Famiglia, but Reborn said that he couldn't share it with the Simon Famiglia since it involved "secret information about the Vongola." Adelheid asked Reborn if he could let them in on it, because the Simon may be able to help. Reborn, however, said that they could help, but also that the Vongola needed some privacy; however, he does ask them to be careful too, since they might also be attacked.
The next day, Adelheid was later seen at the ceremony protecting Enma from being harassed by some of the guests and intervenes. They were later greeted by Tsuna and the rest of the Vongola Guardians, to whom Adelheid asked if Yamamoto's wounds have healed because the Simon Famiglia were all surprised to see Yamamoto at the ceremony. She was later seen amongst the crowds during the ceremony waiting along with the rest of the Simon Famiglia when Tsuna was to receive the Vongola Sin from the Ninth; however, suddenly, an explosion occurred, and the Sin was broken open, supposedly by Enma. The Ninth revealed that the Sin in the ceremony was merely a fake. He proclaimed that the real one was in a safe that was impossible to penetrate. Suddenly, the safe was broke open, revealing Adelheid and Enma with the rest of the Simon, who have claimed that the Sin belonged to the Simon Famiglia and they were there to get revenge on the Vongola. Adelheid tells the story that during Vongola Primo's time, the Simon and Vongola Bosses were as close as brothers, but when the Vongola planned to take over Europe, they wanted to use the Simon Famiglia as bait. Simon's first Boss agreed to this and sent out merely fifty members of their Famiglia to go against an army of 20,000 in order to lure out Vongola's enemies. The Simon waited for their rescue, but no one came. Adelheid claims that the first Simon Boss was ripped limb from limb and the rest of the Famiglia met merciless ends as well, blaming Vongola Primo for leaving Simon's first Boss to die. Not only that, the Vongola blamed the Simon for the incident. After that, the Simon were looked down upon and seen as eternal criminals. But, Tsuna refused to believe the story and responded that Primo would never do such a thing. This, however, only angers the Simon Famiglia even more. Enma said that he would take on the title of the Tenth Simon Boss and get revenge on the Vongola. The Simon Famiglia faced off against the Vongola Guardians. Adelheid and the others then released their rings, as Enma says that the reason that Vongola Primo got rid of Simon was because they had a power that rivalled the Seven Flames of the Sky - the Seven Flames of the Earth. Enma tells Adelheid and the others to stay out of the fight, since he could take on all of the Vongola Guardians. He easily overpowers every one of Tsuna's Guardians. Tsuna tries to take on Enma too, but he was defeated. Adelheid stated that Enma's power was still incomplete, and that he was only using a seventh of the Ring's power. She goes on say that in seven days, the Ring's power would be complete. Dino and the Varia try to intervene, but they are stopped be Adelheid. Enma says that killing would be too easy and that the Vongola needed to feel the pain of the First Simon Boss. Adelheid agrees with him, and the rest of the Simon head back home.
Adelheid and the other Simon members later reappear when Tsuna and his Guardians arrive on Simon Island. Enma and the other Simon members greet Tsuna and the other Guardians. Unknown to the Simon, the Vindice to arrive on the island. This surprises the Simon, Enma even asks if they are human, Adelheid replies that the Vindice were once human, but no longer. She then asks why are the Vindice here, to which the Vindice reply that they are here to honor the agreement between the Simon and Vongola Primo. The Vindice claim that the two Famiglias would have to fight one another, and the loser would go to prison forever. The Vindice take their leave, but before going, Adelheid asks how would they know who wins the battle. The Vindice reply that if the loser's pride is broken, then the other family wins. Simon Famiglia tells Tsuna and the others, that since Simon Island was their home land, they wouldn't engage in battle yet. They would have to follow one road that leads to them. The rest of the Simon then leave.
After the flashback memory of Giotto and Cozzato, she goes to Julie room to discuss about their meeting that has been held. Unfortunately for Adelheid, Julie had only been flirting with Chrome and was unconcerned about what he saw. Adelheid tells Julie that Chrome has no use other than a hostage. But Julies teases her and ask if she was jealous, which angered her. She told him that he is not supposed to be playing around and that she will kill Chrome after they have no use of her, much to Julie's protest. When they arrived at the meeting place to speak about the memory they received after Ryohei and Kouyou battle, Julie simply said that he has no interest in that. As he leaves Adelheid attempts to remind him of his duties as a guardian of Simon. Julie, taking no delight from those orders, grabbed her face and glared at her coldly, reminding her of his displeasure of being ordered around. Then he playfully said not to worry because he will help if things get bad and he never forgot their goal is to overthrown the Vongola.
After the meeting, Adelheid is than shown again receiving another flashback of Giotto and Cozzato. She once again receives memories of Giotto and Cozzato after the match of Large and Lambo. She is next shown after Gokudera defeats Shitt P!. Enma comes to challenge Tsuna immediately and she tries to stop Enma from acting rashly. However, Kato thinks otherwise and tells her to let Enma to be on his own choice. She trusts Kato and restrains herself but still wishes to stop Enma for the sake of the Simon Famiglia. As Enma advances at Tsuna, Adelheid tries to tell Enma that he shouldn't be attacking just yet. However, when Enma refuses to listen, she yells at him that the rules of the fights hasn't been placed out. Enma retaliates, tells her that he is no longer a child and does not want to listen to her anymore. With her boss's order, she have to stand aside helplessly. When Enma's ring out of control, Adelheid confront him and took him back to their hideout along with Julie. She stay beside Enma when he's lying on his bed, having a nightmare and began to questioned Julie who gave Enma the information regarding Tsuna's father. Before she left, she assured Enma that she would purge the Vongola.
She's seen again in her area and challenged Tsuna to a duel as they promised when they arrived. However, they were interrupted by Hibari's arrival who is ready to settle their unfinished fight. Adelheid accepts Hibari's challenge and the two settle on the rules of their match: Battle for the Arm Bands. She then reveals her Flame, the Flame of the Glacier, and uses it to freeze a nearby waterfall; after Hibari equips his Vongola Gear the two stare each other down, finally ready to fight. Adelheid and Hibari face off in front of each other. Hibari lashes out with the first blow with his tonfas, but Adelheid quickly avoids it and dives into the waterfall. She then uses her Glacier flames and creates a gigantic Diamond Castle encasing herself with the waterfall, causing waves of water to lash out and freeze where Hibari is standing. Hibari jumps out of the way. She then reveals that the ice is impenetrable and can repel any flame attack, including Tsuna's X-Burner. Annoyed, Hibari asks how she could acquire his armband when she was inside the ice, Adelheid calmly responds that she wouldn't be the one to take it. Suddenly, out of the frozen remains of the spilt waterfall's water, 500 ice puppets spring out and get ready to attack. Adelheid tells Hibari that his opponents are the puppets, her Blizzardroids.
From a nearby cliff, Demon Spade and a brainwashed Chrome watch from afar. Demon gleefully thinks of his plan and that Adelheid would lead the Simon to victory.
Adelheid orders the puppets to attack, and the nearest ones simultaneously attack Hibari. Suddenly, the ice puppets are sliced to pieces with incredible speed by Hibari, lashing a sharp, long, Cloud Flame-infused chain which seems to have been emitted from the ends of his tonfas. When Adelheid tells Hibari not to get cocky as 493 still remained, he begins cutting down the remaining Blizzardroids and soon destroys them all, much to Adelheid's astonishment. After Hibari cut down all the remain Blizzardroids, he then swifty attacked the ice castle, using almost all his stamina. This attack made a small crack in the castle, in where Hibari planted Roll's spikes in. The spikes propagated, and Adelheid's ice castle was in pieces. Hibari had won the battle against Adelheid.
Later, the Vindice come and arrest her, and then reveal the fourth key which shows that Giotto planned on trying to rescue Cozzato, but Demon Spade requested on going to the Simon's aid himself, proving that he didn't betray him. Hibari then notices someone in the bushes who turns out to be Julie/Demon and Chrome. With the Simon Famiglia gone this far Demon reveals himself along with his plans to everyone present. At first Adelheid is in disbelief and is furious with Demon, but dares not to hurt him out of fear of hurting Julie who was possessed. Later, Kaoru appears from behind Demon and stabs him through the stomach, but turned out to be illusion. She and the others later witnessed the fourth key and find out the truth that Cozzato never died because Giotto had saved him since he saw through Demon Spade's plan.
Before the Vindice took her away, she begged Tsuna to save Enma because she believed that he was the only one capable of fulfilling that request and after asking the favor of the young Vongola. She apologized for all that she had done to them although she knows he might not forgive her.
At the end of Demon and Tsuna's battle, she and the Guardians of both Famiglias are released from the Vindice Prison, reconciling with Vongola. A week after the battle, Hibari left for Kokuyo to fight Mukuro, leaving Adelheid in charge of taking care of Namimori-Middle. She captured Ryohei, Kouyou, and Julie for breaking the school rules, and later punished both Tsuna and Enma for trying to run away from their punishment by hanging them at the top of school rooftop.
Adelheid is seen refusing Enma's request to fight for Skull, misinterpreting his request as asking them to take care of them. After an argument, Adelheid agrees, but still misinterprets it, telling Enma to tuck Skull into bed.
Later, when Adelheid stumbles upon Enma and Skull after nearly getting killed by Team Mammon on the first day of the Representative Battle of the Rainbow, Adelheid thanks Skull for saving Enma and agrees on behalf of the other Simon Guardians to become part of his team in the Representative Battle.
On the second day, no one challenges Team Skull until just before the battle ends, whence a group of Vindice that eventually become known as Team Bermuda appear and defeat all of Team Skull in an instant, stealing their Rainbow Wristwatches to enter the battle as well. Team Skull is mortally wounded, but still alive at this point.