Nelson, Felix, and Katie used to have a team of there own called "The NFK". Both Nelson and Felix hated the name, but they just shrugged it off because Katie was the one who came up with it.

They had gone on many missions together ever since they were 7. Those three were seriously one of the best of friends in the guild.

That all changed when they secretly took an S-Class mission when they were 16, even thought none of them was an S-Class mage yet.

That mission ended with Felix leaving the guild, Nelson to become an alcoholic, and Katie to get severly injured to the point that she couldn't even walk any longer.

Up until this day no one really knows the full story of what exactly had happened on that mission with the three young mages.