Did Blood Nether die unjustly?
Not unjustly!
To say he died not unjustly isn't to say he was unlucky to encounter Zhouyang, who possessed the "Qianyang Treasure Body," but rather because even if he had succeeded in possessing Zhouyang, he ultimately couldn't escape death!
Because Zhouyang appeared here as a trap deliberately set by Cyan Yang Daoist, a precautionary bait!
Cyan Yang Daoist has dealt with demonic cultivators for centuries, and the Profound Sun Immortal Sect, the vanguard against demon dao in the Liuyun Continent Cultivation Realm, possesses incredibly rich experience in demon eradication.
When he decided to pursue Blood Nether, he considered all possible escape methods Blood Nether might use, including "possession escape," which is why he forcibly brought Zhouyang along.
With Zhouyang's Second-Layer Foundation Establishment cultivation, he was absolutely an excellent choice for Blood Nether to possess.