(Yes, this is the same as the page in Vongola101.)
The Arcobaleno are adults stuck in toddler bodies. They still think like adults, and their skills are those of their adult selves.
Each Arcobaleno was given a colored pacifier, to signify their being Arcobaleno. Each pacifier glows whenever another comrade is in the immediate area. They are called the Arcobaleno (Italian for “rainbow”) because each pacifier is a different color of the rainbow.
Not so basic:
In a mysterious program, seven of the best people within the Mafia, from Vongola and from other branches, (I Prescelta Sette, the chosen seven) are converted from adults to babies. The purpose and the process of this conversion is still not known, but it has to do with protecting the ultimate power.
It has also been hinted that each pacifier holds a lot of power. The seven pacifiers are included in the Tri-ni-sette that Byakuran wants to complete.
|Viper (Mammon)||Indigo||Mist||Frog||Vongola Varia|
*Lal Mirch is ALSO Arcobaleno, and should rightfully hold the Blue Pacifier, but Colonello took her place, thus the process ran into problems with her. Her pacifier is thus black, and considered corrupted. It is the reason why she was also susceptible to radiation effects like all the other Arcobaleno, and she has grown older over the ten years between the Varia and Millefiore arcs.