Elias, Shadowbonder Scion

Shadows you control get +1/+1 and have
flanking and "bands with shadows".
At the beginning of each upkeep, you may pay {w/b}. If you do, exile target nonland card from a graveyard, you gain 1 life, create a 1/1 white and
black Shadow creature token, and until end of
turn, Elias gains shadow and becomes a shadow.
When Elias dies, exile all shadows unless you pay
that much life.