Council of Briarwood

Vigilance, Council (This creature can have a
partner if the other commander shares color identity)
Sacrifice an Elf creature: Opponents can't attack
you unless the pay X life, where X is the number
of elf creatures you control until your next turn.
Whenever an elf card enters your graveyard, you
may shuffle it into your library. If you do, you
lose life equal to it's converted mana cost.