Alera, Heavenly Shieldmaiden

Vigilance, double strike, hexproof, flying
When Alera, Heavenly Shieldmaiden enters play,
you gain 5 life.
As long as Alera, Heavenly Shieldmaiden is
untapped, if a source would deal you damage or
cause loss of life, prevent half of that damage or
loss of life (rounded down).
{w}{t}: Gain 3 life.
If Alera, Heavenly Shieldmaiden would be put
into the graveyard from anywhere, exile it.