Awesome / Praefacio Of Blue

• In the very first chapter there's Germaine, Kyle, and the crew of the HMS Victoricia fighting their way through an entire boat of pirates (with Admiral Dylan easily and almost effortlessly sinking five of their companion pirate vessels beforehand). And then of course there's Gumillia helping them escape from the massive Ziz Tiama that attacks the ship afterward by inscribing acceleration symbols on their cannons.
• Right when all hope seems lost and and it seems like Abyss I.R. in Elluka's body will take over Gumillia's body as well, the real Elluka comes forward from inside Gumillia and easily trounces Abyss in a song duel, making the latter break down and throw a tantrum like a child before being expelled from Elluka's body.
• The assault on Castle Hedgehog for the Marlon army, all of them easily cutting their way through a massive horde of undead to give Kyle a chance to get to the queen. The fact that their swords are literally glowing during it due to an enchantment Gumillia put on them is just icing on the cake.
• Kyle defeating Ney by launching her into the air with Chartette's rocket glove.
• From late in the novel there's Riliane and Germaine working together to save Yukina from Abyss I. R.