Heaven's Strike (てんげき, Tengeki) or Heavenly Smite is a Magic used by the Flügel during The Great War and the most powerful destruction magic for Flugel. It was once cast because Jibril was prevented from flying above Elven Gard due to anti-flying zones created by the Elves and casted again after deeming Shuvi Dola a threat.
It's depicted to be a sword/lance-like weapon of light made by channeling spirit circuit's power with Flugel's very own body and condence it in one single, massive blow. The attack itself is so draining that the said Flugel would shrink into child's size for years while magical recuperation is required. And it become the only-named combat technique amongst the race that represent war itself.
The lance itself was strong enough to destroy the capital of Elven Garde in one hit. In V3C1(8 steps left) Jibril also mentioned that even three thousand elves could not block the attack despite all their efforts (although they were able to save some buildings such as the library Riku and Shuvi investigated). As a side effect, Jibril lost her power for 5 years.
At the end of The Great War, Artosh proclaimed he was tired of their pursuits and told the beings there no matter how hard they struggled, they were no match for the heavens. As the Aka Si Anse and E-Bombs were directed at the Flügels, they initiated Heaven's Strike and channeled the energy to Artosh to create a more powerful version of Heaven's Strike, a God's Strike (神撃, Shingeki) or Almighty Smite. The energy was powerful enough to penetrate the core of the planet. It was pointed out by Riku that neither the Áka Si Anse, nor the E-Bomb could match the power of Artosh's Godly Strike.