Blackfeather is consiedered to be an impressive hero especially in low ranks. His amazing assasin skills make him an excellent champion for invading into enemies and kiling the carry without even losing a huge amount of health as he can use his c in order to avoid stans, damage or moving faster. Using his b effeciently is one of the most important things someone should try to master if he wants to main blackfeather. Try using your a at the end as his passive enables him to stack in an enemy and deal bonus damage according to the number of stacks he has made. In both wp and cp builds he is very overpowered at the early and mid game , so invading into the enemies' jg could be a very good decision for the start of the game. I hope i was helpfull!!!

GL!!