Opfert eure Herzen!

Opfert eure Herzen! (心臓を捧げよ!) is the 3rd opening theme of the Attack on Titan anime, and is sung by singer-songwriter REVO of Linked Horizon.

It replaced Die Flügel der Freiheit in Episode 26.

Opening Animation
On a stone ground, a statue of a saintly woman holding a child lays on its side. Surrounding the statue is a ruined city filled with ravenous Titans. A crowd of stationary people stand juxtaposed against a horde of advancing Titans.

In a brightly lit room, Eren equips himself with omni-directional mobility gear, placing his father's key within his shirt. Elsewhere outside, Titans by the dozens wander the wilderness. In a room similar to Eren's, Armin slips his foot into his military boot and Mikasa wraps her red scarf around her neck. In a ruined city up in flames, Titans wander. In the building where Eren and Mikasa are equipping themselves, Sasha helps Conny put on his ODM gear while Reiner beckons to Bertholdt. Levi dons his signature cravat and Hange equips her goggles as Commander Erwin stands outside in the uniform of the Scout Regiment.

Against a brick wall, Christa turns to face someone out of sight as memories of her with Ymir can be seen upon the wall. Ymir also stands against a wall, which shows a vision of a Titan eating a young boy. Outdoors, the Armored Titan marches forward, and Eren's Titan form collapses as it is swarmed by a group of smaller Titans. In Wall Sina, the Wall Titan peers through the ruined stone and a crowd of civilians watches the departure of the Scout Regiment, marching through a long line of illuminated stone columns. Titans consume innocents in the city as the soldiers prepare their ODM gear, standing atop the Wall proudly before drawing their blades and descending into the Titan horde.

Atop the Wall, many Scout Regiment flags fly in the breeze, and the top ten graduates of the 104th Cadet Corps along with Armin stand in salute with glowing hearts. Upon a bed, an elderly hand gently holds the hand of an infant, while elsewhere the Garrison fires upon a Titan at a defensive line.

In an open field, an explosive burst of energy shakes the land, destroying a nearby house. When the dust clears, the Colossal Titan stands beside a mountain, swinging its enormous arm to bring the mountaintop soaring in pieces to the ground below where the Scout Regiment charges forward on horseback. As Jean dodges a flying boulder, Mikasa soars forward on her ODM gear past Sasha to Eren, taking his arm and launching him forward towards the Armored Titan. Biting his hand, Eren transforms into his Titan and charges the Armored Titan, the two monsters raising their fists for battle with hearts aglow.

Across the world, the hearts of many living creatures both living and extinct, bacterial and animal, glow brightly while images of events to come flash by. On a field covered in humans with glowing hearts, the Beast Titan charges forward alongside monstrous animals and dinosaurs, all with hearts glowing brightly. As the humans are flattened in their advance, their hearts go dim.

The ruins of the city with the fallen statue stand empty of Titans. As Eren opens his eyes within his Titan, the fallen statue remains in its place weathered by time.

Trivia

 * The title of the song is a direct reference to the salute of the Paradis Military. Keith lectures Connie during the training days that the salute represents the soldiers sacrificing their hearts for the cause of common good. It also is shouted out loud by Erwin in the battle to free Eren from Reiner and Bertholdt as a means to encourage the troop's morale. Likewise, Eren was disgusted at Reiner pretending to be a proud soldier while remembering him doing this salute.