"Kakashi!" Sensei shouted.
Naruto's came almost immediately after, "Kakashi-sensei!"
The hairs on the back of his neck prickled as they tended to when he was in danger and Kakashi just knew but he didn't move nor make any attempts to protect himself- he kept his eyes trained on the body beneath him.
Sakumo tossed his opponent aside as Minato shouted his son's name, he was running already when Minato's son called out to his son in warning. His chakra was rising preparation for a jutsu before he even knew what exactly was threatening his son, hands flying through seals for the most useful jutsu in his arsenal.
Not protecting his son never even crossed his, even when he stepping between his son and saw that the threat was a Juubi-powered Bijūdama.
He failed Kakashi as a father once already, he refused to do so a second time.
"Tōsan." the word came out like a breath as he stared.
His father's back was to him, hands firmly on the electric barrier keeping the Bijūdama at bay but, even as he watched, the man was turning towards him- one hand moving from the barrier to be placed into the open air between them. A spark and Tōsan grunted before a second barrier was placed- this time excluding Tōsan. A second Bijūdama was being formed as Tōsan placed his back to the first barrier to press both his hands on the second.
Kakashi's mind finally caught up with him, with the implications. "No…"
And Tōsan, Tōsan was smiling at him in a way that made him ache and force himself to remember Rule 25 (A shinobi must never show their tears.). "Kakashi."
He almost couldn't stop his flinch because that sounded like a goodbye. "Tōsan, no…"
"I am so proud of the man you've become and am glad that I had the chance to see it."
He flinched this time and wanted to shout 'You can't leave me! Not again! Not when I just got you back!' and, if it would help, would have begged 'Please Tōsan, don't leave me. I love you. I need you. Please.' but the words were stuck as he stared with wide eyes.
There were tears as the smile grew sadder- as if Tōsan knew what he wanted to say. "I love you, Kakashi. Always."
The second Bijūdama hit then, the first barrier resisting for a moment before buckling, and Kakashi screamed as he lost his father for the second time (as he broke Rule 25). "Tōsan!"