Koth is the first Campaign Planeswalker, and uses a Strength of Stone Red Deck. You will only have a White Equipment Deck and a Mono Green deck when you start out to defeat him. These are his key cards:
3x Spitting Eath 1R
Deals damage to target creature equal to the number of Mountains he controls.
2x Spire Barrage 4R
Deals damage to target creature or player equal to the number of Mountains he controls
2x Koth's Courier 1RR
2x Rockslide Elemental 2R
Whenever another creature dies, R. Elemental adds a +1/+1 counter. 1/1
2x Oxidda Scrapmelter 3R
Upon entering the battlefield, destroys target Artifact
This is unlike the Hands of Flame deck from the other game, so if he pulls out Rockslide Elemental, you have to think if it is worth killing creatures (or getting creatures killed), the other cards are decent counters on your cards, but he should be simple enough to defeat.