SHEN, Limits Broken

Ninjutsu {w/b}
Soulbound (You may pair this creature with another unpaired creature when either enters the battlefield.
They remain paired for as long as you control both of
them.)
I, and the creature I pair with, get a shield
counter. I may perform a new pairing when I flip.
Creatures my owner controls that have shield counters on them have +3/+0.