How many Upagraha are there?
With the exception of Yamakantaka the rest eight upagrahas are malefics and produce bad results. Yamakantaka is powerful in conferring benefits same as Jupiter but the other eight have evil influences in the bhavas (houses) they are found to occupy.
What is Drik Bala?
Drig Bala is the aspectual strength. This is measured by the benefic or malefic aspects to the planet. This strength is gained by the virtue of the aspect (Graha Drsti) of different planets on a planet. The aspect of benefics are considered to be strength and the aspect of malefics are considered to be weaknesses.