Black Fechi isn't so much of a character but rather a people. They were added to the Mint Whelp Saga as the beginning of a minor plot point. Their story is that they left Fechi valley to find their own place. They ended up living in the harsh mountains and it has made them a tough people who strongly distrust any outsiders. Their weapon of choice is the Rotormotor, that using pieces from slain Roflcopters. (you really need to read the Mint Whelp Saga for that last sentence to make any sense.)

Doubt I'll ever use him much.