Accidental Grandparent/Grandchild combo. The girl in the back is Brusquement, who is based on Duramente, the grandson of IRL Air Groove. She's also technically an NPC "mob" uma, strangely.
Though... since Akitsu Teio is in... just chuck in Toni Bianca with Air Groove + Tickezou instead? And another pair with Dictus Striker and NTR while we're at it.