The Corruption

Patron - The Corruption can be your commander.
If it is, begin the game with half your normal
starting life total.
Whenever The Corruption enters the battlefield,
you get an emblem with "At each opponent's end
step, that player loses 1 life and you gain 1 life."
{7}{w}{b}{g}: Exile The Corruption, then return it
to the battlefield under your control.