If youre looking for a tool to keep track of your decks, remember to use Arena Tutor
He seems weaker than some 6-mana 'Walkers (I prefer both Caller of Beasts and Elspeth, Sun's Champion to him), but he's interesting, and he doesn't suck
That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle
Both characters deal their Strength to each other as damage, and a character is banished when damage meets or exceeds its Willpower
Whether its the Archangel Avacyn and Serra Emissary of an Angels deck, a Craterhoof Behemoth in a go-wide deck, or good old Insurrection, game winning spells often cost a lot of mana at least when youre not trying to win with a cheap combo
When you do have a read, it is devastating and when you know a format cold and are really on your game, the guessing can get scarily accurate