When the vicious God of Bats put on a friendly mask and revealed a kind face, it often made people forget what kind of beast he truly was.
Barbatos knew that when Batman Dragon learned he had once been the World Forger's servant, the impression that "Barbatos was a dog" had already begun to take shape in his mind.
Although Batman Dragon would never be careless enough to regard him as a completely harmless dog, Barbatos could reinforce that impression in his mind. He could make his behavior fit Batman Dragon's imagination of a dog, thereby influencing him, causing his impression of Barbatos to deviate, and affecting his judgment.
I, Barbatos, need help. Woof, woof, woof!
Even Batman had his limits. Once this impression became fixed in Batman's mind, it would make people forget his other side—forget that Barbatos was not a friend, but an enemy.
The only reason he wasn't currently using the connection between them to control Batman Dragon and turn him into his true slave was that he had been severely wounded and was suffering from the erosion of Pamu and Empty Hand—not because he didn't want to.
Batman Dragon would never agree to such a thing.
Barbatos understood this deeply.
Batman Dragon had always been on guard against him. When he established a connection with Batman Dragon and granted him the identity of the Barbatos Dragon, Barbatos realized that the other party had used some method to share the burden of his erosion.
(Note: The method involved the other Dark Multiverse Batmen in The Batman Who Laughs' lair.)
Batman Dragon had never trusted him, and what Barbatos was about to do now would very likely be unacceptable to Batman Dragon. But he truly needed to do it, because in the entire Multiverse, he was temporarily short