Mammon approaches Xanxus for a favor. Mammon approaches Xanxus for a favor, something quite unheard of for the money-loving Arcobelano. I feel like this shows his trust for Xanxus despite the fact that Xanxus can be extremely stubborn and cruel. At the very least, it does show that Mammon genuinely values Xanxus' fighting abilities. Mammon is taking a huge risk to ask for a favor, as it deals directly with his curse.

Xanxus already has an idea of what it's about. Much to Mammon's surprise, Xanxus already has a pretty good idea what the favor involves. It surprises me that Mammon would need confirmation on the fact that Xanxus is far from normal. On the other hand, I also feel like Xanxus only openly uses his super intuition in battle. It might be quite the shock for his men to find out that he can use it for insight. I also get the idea that Xanxus probably understood that if Mammon had a favor regarding the rainbow that it would eventually lead to a battle. In best terms, it would also mean a battle with Sawada because his tutor is also an Arcobaleno. Ultimately, Xanxus joins Mammon in the Representative battle as the boss of Team Mammon (the teams are named for and chosen by the Arcobelano). The winner gets their curse removed. Each team consists of one Arcobaleno, a boss, and six subordinates. This means that each team has eight watches; the varia only use six of the eight. The battle is a battle royale against seven teams, with the most important watch being the boss'. When the boss' watch is destroyed, the team is eliminated.

Xanxus and Mammon, ready to go! It is revealed that the Representative battle is actually to create the next generation of Arcobaleno. Xanxus fights in very few major battles. The very first day of battle, his men do all the fighting. When the hotel is attacked, he gets involved but only because they disturbed him. In fact, Xanxus treats the first few days of the battle as a vacation in which he sleeps and eats for the majority of the time. Despite his cat like personality, Mammon trusts and relies on his boss.

I also want to note that he wants to fight Hibari, but Dino says something about Tsuna which makes Xanxus mad. His temper flares up immediately and he and Hibari fight. When the watches announce the end of battle time, Hibari destroys his own watch to keep fighting. The rest of the Varia stop Xanxus from breaking his watch. Most of Xanxus' team is actually eliminated by Hibari or the Vindice. Xanxus sustains injuries during these battles but is not eliminated. Eventually the battles become one sided with the Vindice dominating the field. Tsuna starts collecting extra watches and begins calling all of the Arcobaleno teams together to form the Allied team. Xanxus and Squalo join this team and are specifically put onto the Elite Squad alongside of Dino, Byakuren, and Mukuro. Xanxus' anger and resentment towards the Vindice is much greater than his anger and hatred of Tsuna, I believe this is the only reason he agrees to the allied forces - otherwise he'd have had some grand plan to kill the Vindice himself.

Elite Squad - A dangerous buncha dudes! Unfortunately, the Elite team is easily dispatched. They take a great many injuries, though Xanxus' scars appear when Squalo takes a blow to the chest and cannot take his orders. Specifically, Xanxus loses his right arm and takes severe damage to his kneecaps. He is shown healing, and when someone gets on his nerves he destroys part of the hospital. Though, I do feel it is extremely important to note that Sawada believes that Xanxus is someone that he can rely on. He still relies on his rage as a driving force behind his abilities, but I feel by the end he ranks the Vongola Family's strength his highest priority despite its boss. Rather, I feel like without question he assists as long as it is to the benefit of the family versus aiding Tsuna. In short, Xanxus puts the family needs before his own rage, but still refuses to support its boss.