Ezio plans to leave for Spain but was rebuffed by Mario , who then sends Ezio on a errand to get some armor and a dagger " return to me when you are done. " Reluctantly Ezio does so while Ezio is off on his errand , Mario tells Izumi to get in the training ring with Ezio handing her a training blade " do not go easy on my nephew " he finally said.
Ezio soon returns from the errand and was pushed into the training ring with Izumi a training blade in his hand. Ezio still doesn't believe in the existence of Templars and Assassins " it reeks of fantasy " still believing that his father were bankers then turning to the other person in the ring with him.
" why is that person here as well ? "
Mario laughs at the thought " No my nephew I will show you , the Assassins very much exist, Now defend yourself. " Izumi used Mario's command as a cue to attack. Ezio turns his back to his uncle and Izumi " I had enough. " Ezio is then met with a sharp rasp to his back as he was wracked loudly across his back by Izumi.
" Never turn your back to the enemy " Mario then continues to shout instructions to Ezio , when they finished Ezio dropped to the ground and groaned. He hurt everywhere Izumi had not been gentle with the training sword. Ezio is now covered in bruises on both his arms and back.

Mario continues the lessons of swordplay with his nephew Ezio for the next several days. Over time Ezio begins to get the hang of it , but is always on the receiving end of the attacks barely able to hold off for more than a few minutes. The training sessions often end with a very frustrated Ezio, believing that his is just another one of his uncles stories and games thinking ( " how am I going to pratice when I am being forced to fight a fully trained Assassin , I feel like a punching bag. " )
Mario then tells Ezio to meet him in his office " there is something I wish to show you. "
After heading there Mario then presses a switch in the back of one of the shelves revealing a stairway and tells Ezio to follow. He leads his nephew to the basement of his office. The next room is rather large inside are several statues of past assassins. Here Mario reveals the history of the Assassins and their age old war with the Templars , but the assassins are not alone they had allies a Japanese ninja and assassin clan known as Hayabusa they are the guardians of a certain artifact that I will not speak of as well as the pieces of eden, and is also our job to protect them as well.

After they are done Ezio thanks his Uncle for giving him the skills he needed. Mario then asks Ezio if he had reconsidered leaving. Ezio then claims that he will leave after 3 days and set sail for Spain if there are any enemies he will kill them. Mario then gets furious with Ezio. Enraged, Mario left Monteriggioni for the city of San Gimignano, where Vieri had been located, in an attempt to relieve Monteriggioni of continual assaults by the Pazzi's minions.
Ezio then looks at Izumi who was standing nearby " why is he angry ? "
" You know the answer to that question better than me , truth is you are denying your rite of birth something your father gave his life for. Mario told me some things , go to him " Izumi responds. Guilt-ridden and knowing his presence was a primary reason for the ongoing attacks, Ezio traveled to San Gimignano to accept Mario's offer taking Izumi along.

Upon arrival Mario was surprised " Ezio why are you here ? "
" your target troubles you because of me , I wish to help . "
Mario then corrects him " No he troubles us because he is a Templar and we are Assassins , now listen closely this is how we will strike. " Mario then points out the weakness of the target and leads Ezio and Izumi there telling them to dispatch the archers inside from afar then open the gate " take these with you. "
Izumi lets Ezio take hold of it since the shape of the throwing knives are unfamiliar to her , preferring the use of her kunais instead. The two then scale a wall pinpointing four archers , Izumi then points at two of them then herself and then to Ezio and the remaining two. With a nod the two begin their act quickly dispatching all four targets. Ezio then opens the gate for the strike team. At first Mario plans to kill the target himself but his plans hit a snag so he tells Ezio and Izumi to finish it.
After witnessing a brief meeting between Rodrigo Borgia, Jacopo de' Pazzi, Francesco de' Pazzi and Vieri, Ezio made for his target joined by his partner Izumi. While Mario and his mercenaries kept Vieri's men distracted.
The two then get on a roof leading to a tower where Vieri is at.
Izumi draws her sword and puts it in her mouth intending to carry out the kill on her own but was blocked by Ezio " no this is my fight. "

Ezio challenged and fought Vieri for the last time, eventually overpowering and killing him after a brief duel. Ezio tried to extract a confession from his old enemy, though Vieri chose to be snide to the very end. Infuriated by this, Ezio flew into a rage and insulted Vieri's corpse. Izumi herd the shouts and moves in to investigate.
When she sees what is happening she calls out to him " EZIO , Stop ! Remember what we fight for , we are assassins not Templars show some respect since those are still people "
Izumi then takes a letter from Vieri and hands it over to Ezio telling him to read it when he has time.