Elaina Viess, Regent Heir

Haste, Double Trample, Soulshift 10.
Your spells each have Convoke.
Become Stronger—{t}: Put a +X/+X counter on a creature you control, where X is the power of the highest-power creature you control.
{g/u}{p/u}{p/g}: Until end of turn Elaina has all the
abilities of all creatures in play and in all
graveyards.