Obito's "death" made the two of them lose all reason.
Otherwise, even a moment's thought would have revealed that something was wrong.
When Obito was still there, that group of Stone Ninja had managed to seize an opening to "kill" Obito Uchiha. Now that Obito was "dead," did they really need to flee?
Unfortunately, Kakashi and Asuma were all too easily lured away by White Zetsu disguised as Stone Ninja.
"They're so easy to fool." After Kakashi and Asuma left, Black Zetsu emerged from underground with a quiet chuckle.
Black Zetsu glanced at Obito, then pulled him straight underground.
Whoosh! Whoosh! Whoosh!
Enraged, Kakashi and Asuma fought at 120% of their strength and quickly wiped out the White Zetsu Clones.
Of course, that was also because Black Zetsu and the others had already succeeded in their scheme and no longer needed these Stone Ninja.
"Something's wrong. These Stone Ninja aren't as strong as they should be. We've been tricked!"
Watching the Stone Ninja's corpses vanish, Kakashi regained a measure of clarity.
"Asuma, hurry back! We've been tricked! The enemy might be after Obito's body!" Kakashi gritted his teeth. He hadn't expected the enemy to refuse to leave even Obito's body alone.
"What?" Startled, Asuma hurried back to their previous location with Kakashi.
But the spot where Obito's "corpse" had been was now completely empty.
How could Kakashi and Asuma fail to realize that the Stone Ninja had deceived them?
Kakashi angrily slammed a fist into the ground, oblivious to the blood covering his hand.
"Damn it, we're too late. I never thought the enemy would refuse to leave even your body alone. Obito, I'm so sorry."
"I'm sorry, Obito. I couldn't even keep your body safe." Asuma stared at the empty spot where Obito's body had been, clenching his fists