Well, I think I have a deck that can defeat all three of the final bosses. Survival requires insanely exact card draws, but that’s how these were designed. I’ll provide the listing and then a tactical walk-through.
The deck depends on boosting tough creatures and then Gabrian Enchantment for the win. I tried it without the blue for consistency, but there was just no way. I would love to include Dragonslayer but I have yet to own one!
Oh, and you don’t need Mythics. I think three of my included cards are fancy, but that’s it.
3x Falcon Dive
3x Hold the Line
1x Defender of the Homeland
2x Ruunin’s Shrine
3x Gaea’s Grace
3x Ruunin’s Guidance
3x Shamanic Dance
3x Elderwood Embrace
3x Living Willow
3x Possessed Ursus
3x Gabrian Enchantment
Raizeon has 40 health and you need to take him down in one turn or lose all your lands. There is no recovering from that. The other trick is that after turn six you will get hit with Godfire Storm, which does 10 damage to all your creatures. You play around this by either a) waiting until after turn 6 to play Ursus, or b) having an Ursus with sufficient health on the board at the time. The former is actually easier, since you can save up the perfect hand to play Ursus after the storm. Pump his Health to 20 or more, play Gabrian Enchantment and then Falcon Dive your own bear. It’s actually not difficult.
Jalmyr has 50 life and will steal any critter that hits him. So again you need to hit the orb with enough to kill him in one swing. Possessed Ursus is again the best bet. The huge obstacle to overcome is that the cost of your cards increases every turn they are in your hand. So you need the cheapest possible cards. That influenced my deck design.
The strategy is to lay forests and lakes straight up the middle, or almost straight. This depends on where Jalmyr plays his first Wandering Monk, since this will be a 7/5 to start. This threat needs to be avoided initially. Otherwise it takes down the Ursus health so much he is useless.
The best play is to put out a Living Willow early, to buy time and maybe take out a couple of annoyances. Don’t be afraid to use up your faeria pumping it up. Soon those cards will be too expensive to use and dead in your hand. Getting to 5 power to kill the first huge Monk is important.
Your opponent does you a favour by playing Hunted Outlaw. This is a good second target for the Willow, as it gives you card and faeria advantage. I use this to ramp up my Ursus, which should be the second critter played. I added the Ruunin Shrines, as these tip the balance again slightly in your own favour and help counter the cost creep of cards in hand.
You need to draw into an Ursus at just the right time, boost his health with all the pump cards in order to get to 13 or more. Then use Gabrian Enchantment. From here you need to kill one creature and then Falcon Dive the bear. Voila! You have over 50 attack and can kill Jalmyr.
You will lose if your foe plays a Doom Scythe.
Against this insane deck you use the Falcon Dive’s offensively to pop bubbles, and the Gabrian Enchantment likewise to whittle down the enormous power you will be facing. You win through taunts, of which there are 14 in the deck. You don’t have enough creatures and so need to be extremely lucky to get the right ones at the right time against the array of offence. This is actually a bad deck for this boss.