As long as you control three or more legendary creatures, Kolvori gets +4/+2 and has vigilance.
, 
: Look at the top six cards of your library. You may reveal a legendary creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
//
As The Ringhart Crest enters, choose a creature type.
: Add . Spend this mana only to cast a creature spell of the chosen type or a legendary creature spell.