Essence Beast
The Attribute Strengthening Spark was an orb the size of his head. It was tremendously tough as Compass Carburettor hacked it repeatedly for more than a minute using his energy blade sword before cracking it.
And in this duration, the surrounding cultivators had indeed noticed his actions, intending to snatch the Attribute Strengthening Spark from him. But, the ethereal creature's body acted as his shield.
And for most, they were unable to enter its body, as it has a corrosive property, enough to melt their bodies. For those with the tower's shield, they noticed that even though they could move through its body by relying on that, the shield lost strength too fast.
It wasn't worth it to waste their shield for something they might not obtain. After all, they still had to fight against Compass Carburettor to snatch the Spark.