Disclaimer: I don't own the rights to Laura Marling's "Alas, I Cannot Swim", her song "Your Only Doll (Dora)" from said album, nor Eyeshield 21.
The Old Man with the kindly cruel voice that was unfathomable was actually sad to see Sena leave. It wasn't just the loss of a charge, though that was a very real part of it, but He would miss Sena's bright soul following him, Sena knew. There was an ease of connection in death, soul to soul; that's not to say that everyone will magically be telepathic in death, but, well, there was something in the Old Voice that Sena could feel and could be felt.
He could feel the irritation/rage/fear of losing a soul, though there was a real feeling of fond exasperation. He knew that Sena wouldn't stay, He could feel it in his old, old, old bones—older than dirt, younger than time, was the joke—what could he do with a Soul that refused to belong to him fully?
The Old Man was the one who guided them out, Sena and his Juumonji, lead them out of death and staved off the voice. He was silent and stoic and fond and roared back at the voice that "A deal is a deal. You cannot cheat death so death will not cheat you."
Sena would never long for death. He would cherish every—every—second that his lover had carved for him, literally, but when his final day came for the final time, he could think of worse ways than to go softly, hand-in-hand with the kind Old Man who guided him into and out of death.
Two more weeks.