So, this boss appears to be the type that grows stronger as the battle continues on. He would recover more HP if more players were to attack him! Theoretically, the 300-meter radius area around the boss should be able to hold quite a substantial number of players.
Hulkinsh was rather similar to Angus. They were both the type of bosses that would become even more fearless if they were to battle a larger number of enemies. It would best to battle these bosses with a bunch of elites!
Of course, that would work for the other players.