Colfenors high toughness will allow you to bring other treefolk back from your graveyard, and combined with Doran, the Siege Tower, they can deal massive amounts of damage together
That's why Upheaval is such a bomb: there are virtually no ways to deal with it, and once it is cast you can end up with two to three creatures plus a land on the board while your opponent literally has nothing, and has a hand full of sixteen cards they need to discard down to seven
Blue-Red Delver -2 Exhume -2 Grief -1 Dark Ritual +2 Silence Matchup: Jeskai Control Jeskai Control: Mainboard 0-2 Hullbreacher 0-2 Supreme Verdict 0-2 Days Undoing 0-2 Dress Down Jeskai Control: Sideboard 1-2 Flusterstorm How To Sideboard vs
This creates infinite 1/1 tokens that will win the game as soon as you can attack with them
But the real reason Bruvac is so powerful is that theres an entire class of card, all of the variants of Traumatize, that makes an entire player's deck go poof when resolved with Bruvac in play
Mid level cards that are decent threats or let you go big in relative safety are really nice additions
