Verde asked Parenza and Tras to assassinate the Vongola 10th candidate, Tsunayoshi Sawada, with a poison. The plan failed when Basil and I-Pin came and fought them and won with the help of Ryohei and Yamamoto when Basil cut the trap with his Triangular Blade.
The 10-years-later version of Verde was one of three scientists who developed the Box Weapon along with Innocenti and Koenig as part of the same secret society. Like the other Arcobaleno, he was affected by the Anti Tri-ni-sette Radiation. As with Innocenti, he also mysteriously died.
During the Trials, Verde is often behind the scenes having people test out Box Weapons for him. First he had Viper test them during his Trial, then he sent out hitmen to attack Tsuna and Aria during her Trial. During the Arcobaleno meeting, Verde is busy with testing out Box Weapons in a simulation against the other Arcobaleno and is the only one not present. He decides to take the Vongola Rings for himself to continue his work and sends out several Box Weapons, along with other inventions, to attack the Vongola Guardians. When Reborn questions if this is his Trial, Verde merely responds by saying he is only after the Rings and doesn't care about the Arcobaleno pact which lead Reborn, Colonnello, and Lal Mirch to enter the fight, as he had broken the Arcobaleno pact. Eventually all of the Arcobaleno show up during the battle, to Verde's expectation, as he uses something similar to the anti Tri-ni-sette to completely weaken them and holds them hostage for the Vongola Rings. After being refused, Verde sends out Lightning Starfish Box Weapons to collect data on the Dying Will Flames of Tsuna, Yamamoto, Gokudera, and Hibari.
Verde absorbs the Flames to where he believes to be their maximum potential and releases four Box Weapons with each of their Flames. At first, Verde seemed to have an advantage, but they use their resolution to fight the Box Weapons. Tsuna headed towards the device emitting Non-7³ waves and destroys it, leading Verde to destroy the Pawn Missiles holding the Arcobaleno, though Verde's efforts fail as the Arcobaleno were hidden in Mammon's Illusion. After the Box Weapons are destroyed, Verde tries to attack them with his Lightning Flames that hurt and paralyze everyone except for Lambo, who gets mad and tosses grenades all over the ship. Tsuna ends the battle by using X-Burner: Air only to realize that he had only destroyed a robot, used by Verde as a decoy. The real Verde was found hiding on a bumpy rock island. Despite not obtaining the Vongola Rings, he had obtained valuable data to complete his Box Weapons. Verde gives Tsuna his seal for finishing his Trial of Intuition, which was cleared when Tsuna found where he was hiding. He escapes while activating a self-destruct on the island.
Verde and the rest of the Arcobaleno are called by Reborn to train Tsuna and the others, each member of Tsuna's Family paired up with the Arcobaleno with the same Flame. Unlike the other Arcobaleno, Verde didn't show himself until Lambo's test, where he once again showed his unwillingness to help. Instead, he performed tests on Lambo as he was interested in how Lambo was able to endure so much electrical shock, stating that he had shocked Lambo with enough electricity to "power the entire town" and that he was merely fueling his ambition. Later, he also sent robots after Lambo to try and harness that Ability. When those robots were defeated by Tsuna's Guardians, he took Lambo in a larger robot, controlled manually by himself. However Lambo, who became frightened, set off a huge electrical charge and destroyed the robot.
After being revived by Uni along with the rest of the Arcobaleno, Verde quickly showed his intellect, by explaining that the re-writing of the dimensions by sealing the Mare Rings in the past was "a miracle" to Shoichi Irie. Tsuna commented that he spoke way too maturely for how he looked. He later assisted in returning Tsuna and his Guardians to the Past, at the same time transforming their Vongola Box Weapons into Vongola Box Rings, explaining that he would not betray them, as he had a debt to repay to Uni. After sealing the Mare Rings in the Past with the other Arcobaleno, he returned to the Future to find the Future Vongola.
Verde, like all of the other Arcobaleno, had the same dream, meeting Checker Face, who offered to revert the strongest Arcobaleno to his original form, provided they find someone to fight for them. At first, he expresses his disbelief over the man's trustworthiness, but after the man threatened to leave them with their infant body for the rest of their life, which the other Arcobaleno agreed to, sans Reborn, Verde agreed, saying that it would be exciting. Later, he is shown to have gone to Kokuyo Land to request Mukuro Rokudo's help. Later, he appears at Namimori along with the Kokuyo Junior High Gang, accompanying Mukuro, who went to declare "war" on Tsuna and his Guardians. The night before the Representative Battle of the Rainbow started, Verde unveils to Mukuro his "new-generation weapons."
After the Vindice's ambush on Mukuro's team, Verde started to lose interest in the Representative Battle finding it boring. He explained that he never really care about his curse and participating just because he wanted to give Reborn a good scare. However, since the situation started to become dangerous and he cannot focus himself on his research, he told Mukuro that he can quit whenever he wants to. Mukuro refused this offer since he needs something in the Representative Battle. At the start of the third battle, he and Reborn formed a temporary alliance to defeat the three Vindice that attacking them.
After Reborn and Tsuna returned from the Vindice prison, he and the other Arcobaleno gathered to discuss Bermuda's plan. When they heard Reborn's possibility to join Bermuda in order to destroy the Arcobaleno system, Verde objected the idea, stating that he refuse to die because of someone else's scheme, causing him to being punched by Reborn and the meeting become a huge argument. After witnessing Tsuna's resolve and plan, however, all of the Arcobaleno agreed to work together to defeat Bermuda.
During the fourth battle, he, Spanner, and Shoichi Irie create the Decoy Puppet for the Allied Teamto use. When Squalo, Byakuran, and Xanxus are defeated by Jaeger, cornering the team, Verde use his curse release time to become adult and fight Jaeger by riding Green Moska that he, Spanner, and Shoichi have made specially for the battle.