Head of Boe Jiden

Head of Boe Jiden gains +1/+1 for each card with "Boe Jiden" in its title in your graveyard. If all four are in your graveyard, convert Head of Boe Jiden.
{2} Sacrifice a creature. You gain 2 life, and
Head of Boe Jiden gains protection against everything except blue until end of turn.