User blog comment:B214/Volume 23 discussion blog/@comment-201.215.165.7-20170710225539/@comment-31137559-20170711123454

She traded over Asia and Xenovia to him because they wished for it. And then later she traded over Rossweisse over to him because she felt Rossweisse would be of more use to Issei than her. So Rias now has an unused bishop, knight, and rook piece.

And for the Azazel Cup, anyone can register as a king and have up to 15 team members(based on peerage roles). Devils that already have peerages can compete with them and add in some other team members. For example, Lint Selzan is filling in the knight position for Rias' team. She's just a team member, and not in her peerage. And she is basically an artificial human created with the genes of Sigurd to create those who can wield Gram and her and Freed were created from the same set of genes which is why they look so identical. And she is now the possessor of Incinerate Anthem and was recommended by the Church and Grigori for Rias' team.