"...we did not part on particularly good terms."

Sure, Yamato saved Hiro- Kaito, he needed to get used to that - by blasting him out of the way of Tsuutenkaku, but a pained minute of his last words weren't enough to dispel whatever bad feelings may have lingered over their differences.

Truthfully, he thought if he ever saw Kaito again in the afterlife - preferably after Kaito lived a long and happy life - he would understand if the brunet wanted nothing to do with him any more.