User blog comment:B214/Question and Answers 4/@comment-24173056-20150227193909/@comment-26268422-20150406022123

Ichibumi might further develop the SG and I'm thinking he could do something like have the 2 pieces plus the sephiroth grail acting as a substitute might be able to summon the 3rd piece. It would make a certain amount of sense. However, there is no indication of just where he is going with this since it just seemed to revive Valerie and then they left it at that. Whatever he does, it'll just Ichibumi-san building in his usual hidden features and bringing them out when the chips are down. From his writing style, I'd say Ichibumi himself is the unnamed architect that is sponsored by Ajuka-Beelzebub that designed Issei's house with features that only reveal themselves under just the right circumstances.