They’ll haves ‘seggs’ when Tsukasa becomes mortal again and there’s no longer risk of bad shit because of immortal regeneration shenanigans like eternal blood rivers with excruciating pain, emasculation risk, or sterility. At least, I highly suspect these issues, and have, for awhile.
Reminder the first Ch.140, the ‘XXX’ chapter flash-forward, seems to imply she will be made mortal again (that is, made her ‘wish’ come true) by December in the story.