Once you get in to Facterial town, and get numemon to yuor city. Go back to the sewers and then you'll find Nanimon. Once you talk to him he will run then drops a blue key chain.(Can also find him to drop blue key chain in anceint speedy region were Meteormon is.) Then go to were you beat the bandits in there orge fortress in the Grand caynon. Then Nanimon will drop a red key chain.