Akira, Solemn Defender

As long as you control four or more Knights,
Auras you control have indestructible.
{2}{g/w}{w/u}{t}: Unattach all Auras from creatures
you control. Auras you control become X/X creatures until end of turn, where X is the
number of Knights you control. At the
beginning of the next end step, reattach all
Auras unattached this way to creatures you
control.
She defends those who cannot defend themselves.