Which hero has the ability 'Defense Matrix'?

The Overwatch hero with the ability “Defense Matrix” is D.Va.

D.Va is the callsign of Hana Song, a South Korean former professional gamer who pilots a MEKA combat suit. Defense Matrix projects a field from her mech that intercepts and destroys many incoming enemy projectiles. It is especially valuable for protecting teammates from powerful attacks, although it does not block every kind of damage and must be aimed toward the threat.

Her ability kit reflects the contrast between mobility and defense. Boosters let D.Va fly toward her target, Fusion Cannons provide sustained close-range fire, and Micro Missiles add burst damage. If her mech is destroyed, she ejects and fights on foot with a Light Gun until she can use Call Mech to return to the suit.

Defense Matrix has been adjusted several times. In the original game it worked as a limited resource that could be activated and drained; earlier versions used different cooldown and duration rules. Blizzard also introduced changes to reduce how completely D.Va could depend on it while encouraging more aggressive play. It is not her ultimate: her signature ultimate is Self-Destruct, which ejects and detonates the mech.