The note you found carries the seal of Black Cloud Traders. Give it to Tienshunerk.
Step 1. Talk to TienshunerkA Black Cloud Trader at the Twilight Battlefield. He is quite fearless for a Shugo..
Step 2. Talk to KohrunerkA Black Cloud Trader at Black Cloud Island in Reshanta. He has many secrets..
Step 3. Talk to KierunerkA Shugo belonging to the Black Cloud Traders in Outer Dock. He has a great talent for business..