Lyra Dawnbringer

Stack three keywords that defend a body from every angle of combat and you get a creature that almost cannot lose a fight: first strike kills attackers before they connect, flying lets it choose which combats to enter, and lifelink turns each swing into a life swing the opponent has to race twice over. That bundle has a lineage in white's top-end Angels, where Baneslayer Angel set the template for a five-drop that single-handedly flips a board state and gains life faster than burn can answer. This pushes that template further by extending the lifelink to every other Angel you control and pumping the squad, turning a solo threat into a tribal anthem that makes a wide Angel board nearly impossible to attack into profitably. The legendary tag is the cost of that ceiling: one copy at a time, no doubling up on the engine. What keeps it honest is the same thing that has always kept big white fliers honest, a five-mana investment with no immediate board effect and a clean weakness to removal that ignores combat entirely. Resolve it and buy a turn, though, and the math runs away: a 5/5 first-striking lifelinker is already a wall, and a second Angel beside it makes the whole formation gain life on every block and every swing.