Kid A and Kid B meet at Kindergarten.

Kid A is social in play, kid B isn't. Kid A approaches B and become friends.
Kid B doesn't actively seek for kid A, but in it's presence they both play together.
Kid A seeks for other kids to play, spending time with Kid B, but also with other more socially active Kids.

In Elementary School Kid B and Kid A both keep contact and interaction in a stable way but agression grows.
Kid B mocks Kid A with nicknames (I.e "Hypocritical Opportunist")
Kid A won't respond emotionally to them, but after a while punches Kid B in the face unexpectedly.
Kid B won't fight back.

Kid A and B keep on being friends.
Kid A is perceived as socially popular, but remains acting individually in groups.
Kid B is perceived as non involved and acts unpredictably.
Kid A becomes popular leader for pranks and other kind of mischief
Kid B is suspected to participate in Kids A mischief in an unpredictable basis
Kid B is suspected to colanorate with Kid B in the manipulation of others
Kid's B individual efforts towards mischief haven't been discovered.