Gehenna Guardian

When fed up from all the hypocrisy and scorn he received, Rin decides to run away. From the Exwires, his family and True Cross. It's not his fault when the Paladin decides to 'help' with it.
During his travels with only Kuro by his side, he decided to hide right under the Vaticans noses in Italy (where there main HQ is). What he didn't account for was to stumble into a scirmish between the Vongola guardians during an ambush.

Watch what happens when two underworld's meet different demons.