Cenn's Heir

Whenever Cenn's Heir attacks, it gets +1/+1 until end of turn for each other attacking Kithkin.

Wizened Cenn

Other Kithkin creatures you control get +1/+1.

Kithkin Harbinger

When Kithkin Harbinger enters, you may search your library for a Kithkin card, reveal it, then shuffle and put that card on top.

Rustic Clachan

As Rustic Clachan enters, you may reveal a Kithkin card from your hand. If you don't, Rustic Clachan enters tapped.
{T}: Add {W}.
Reinforce 1—{1}{W} ({1}{W}, Discard this card: Put a +1/+1 counter on target creature.)

Mutavault

{T}: Add {C}.
{1}: Mutavault becomes a 2/2 creature with all creature types until end of turn. It's still a land.

Kinsbaile Borderguard

Kinsbaile Borderguard enters with a +1/+1 counter on it for each other Kithkin you control.
When Kinsbaile Borderguard dies, create a 1/1 white Kithkin Soldier creature token for each counter on it.

Plains

Augury Adept

Whenever Augury Adept deals combat damage to a player, reveal the top card of your library and put that card into your hand. You gain life equal to its mana value.

Brigid, Hero of Kinsbaile

First strike
{T}: Brigid, Hero of Kinsbaile deals 2 damage to each attacking or blocking creature target player controls.

Honor of the Pure

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Figure of Destiny

{R/W}: Figure of Destiny becomes a Kithkin Spirit with base power and toughness 2/2.
{R/W}{R/W}{R/W}: If Figure of Destiny is a Spirit, it becomes a Kithkin Spirit Warrior with base power and toughness 4/4.
{R/W}{R/W}{R/W}{R/W}{R/W}{R/W}: If Figure of Destiny is a Warrior, it becomes a Kithkin Spirit Warrior Avatar with base power and toughness 8/8, flying, and first strike.