I believe he is referring to a publishers deadline, for GXP #9. From what I’ve read Mizuki penned Paradise War #1 for him because the writing for GXP #9 was running behind schedule. I’m going to go out on a limb and say Kajishima is likely paid in advance, like a number of authors in America are. If so, they probably issue a penalty for every so many weeks behind schedule his final drafts are submitted. Or it could be that the publisher runs a very tight printing schedule, where any delay would significantly push back printing by rescheduling that title several weeks later. In any case, the important part is that he handed off Paradise War to Mizuki so he could finish up GXP #9, then get it to print on time and this is what he is referring to.
