Soulbound Guardians

A 4/5 flyer behind a wall: that contradiction is the whole point. Defender locks the body in place, but flying means the thing it defends against doesn't have to come to it. Most defenders are ground-bound, plugging the lane the opponent's creatures want to walk through; pairing the keyword with flying turns the card into an air-superiority piece that can block almost anything an opponent flies in while contributing nothing to the offensive clock. The 5 toughness is the number that matters here, sized to survive the combat trades and burn that smaller flyers fold to, so it sticks around as a permanent ceiling on the opponent's evasive damage. It is a defensive specialist with a narrow, well-defined job: shut down the air without ever advancing your own board. That single-mindedness is also the limit. A creature that flies but cannot attack is asking to be built around by decks that wanted a wall anyway, which is a narrower ask than a card with this much toughness usually gets to make.