Silverblade Paladin

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)

As long as this creature is paired with another creature, both creatures have lifelink.

Whenever you gain life, put a +1/+1 counter on this creature.

As long as you have 25 or more life, this creature has double strike. (It deals both first-strike and regular combat damage.)

Double strike

Creatures you control with first strike have double strike.

This creature has double strike as long as you've committed a crime this turn. (Targeting opponents, anything they control, and/or cards in their graveyards is a crime.)

During your turn, this creature has first strike. (It deals combat damage before creatures without first strike.)

During your turn, creatures you control with +1/+1 counters on them have first strike.

As long as you've completed a dungeon, this creature has double strike.