Miyu finds a Master-less Servant and makes him her Servant, and from then on she easily keeps him in check whenever he acts up or even behaves rudely. The reason this is such an awesome achievement? Her "new Servant" is frickin' Gilgamesh.
As usual, Archer is good for this. He uses Unlimited Blade Works to generate Rings from all of the various Corps, including White. And in the process, causes an explosion visible from space. Twice.
The battle between Invader-Godzilla and Evangelion-Combining Mecha is made of pure win. Capped off with Fate Testarossa's new "Ionic Piercer" attack, which is "to lightning what a god is to an amoeba".
Nanoha's epic lecture to Reinforce for even considering giving up and sacrificing herself so easily after everything done for her sake is incredible:
"Too many people," she said, voice quiet, soft and gentle, yet completely immovable, "have died so that you may live. Archer-san, who I've only met once… Berserker-san, who died before my very eyes… they gave their cores to you, freely and of their own will, knowing they would die, yet gave them to you anyway, so that you could be completed. So that you and Hayate may live. Their deaths gave you life." Nanoha lay a hand over her own chest. "My core is a part of you, Reinforce-san. A part of me helped give you life. You are my responsibility." Nanoha's visor dissolved, and the gaze that met Reinforce's eyes were hard. "How dare you think to repay all those sacrifices with your death, Tome of the Night Sky? How dare you?-! Too many people have died to give you this life. I refuse to allow you to make all those deaths, all our pain, all of the knights' suffering, Hayate's loneliness, be in vain. For the sake of all those who've died, Tome of the Night Sky, you are going to live. You are going to live and bring the happiness and joy they weren't able to bring to the world. You are going to live and give their sacrifice meaning. You are going to live, and be happy with those you love, in memory of those who cannot be, to enjoy the life they gave you at the expense of their own. And if I ever hear any of this nonsense again…" At this, Nanoha's voice actually gained a touch of menace. "I'm telling Hayate-chan."