Livio, Oathsworn Sentinel is a rare Legendary Creature — Human Knight card from Commander Legends (CMR), collector number 551.
{1}{W}: Choose another target creature. Its controller may exile it with an aegis counter on it. {2}{W}, {T}: Return all exiled cards with aegis counters on them to the battlefield under their owners' control. Partner (You can have two commanders if both have partner.)