User blog comment:B214/General Discussion/@comment-4547267-20161206203653/@comment-9595671-20161208000520

While I know familiars can be summoned, it seems like they're not allowed to fight, only do reconnaissance or set traps. So even if Asia could summon them I don't think they would be allowed to fight because they're not in Issei's peerage.

I mean if you think about it, being able to increase your numbers and then allowing those additional forces to also fight would be unfair unless it's something like a sacred gear user copying themselves because it's still technically the same person.