1(Crossover)

An Au where Kageyama Tobio and Murasakibara Atsushi are cousins or step-brothers and very close.

They are always there for each other in their moments of need or as soon as they can and try to encourage each other with this being the reason why both still play volleyball and basketball instead of giving it up after what happened in middle school.

Also, I just imagine in both of their last games(Karasuno vs Shiratorizawa & Seirin vs Yousen) the other being there and being their biggest cheerleader(well, Murasakibara would just be there....being his giant self while eating sweets and just observing Kageyama but it still counts).

Not many things for this au in my mind but it would be interesting to have Seijoh, Karasuno and other teams meet Murasakibara(and maybe the other Miracles and their teams) and seeing their reaction at knowing that this purple haired lazy giant who loves sweets is the cousin/step-brother of their grumpy awkward setter.