Shingeki no Kyojin, Nejimaki Seirei Senki: Tenkyou no Alderamin Recommendations
Both shows are set in a steampunk world, where the main weapons being used are swords, rifles and canons in both. Both anime feature a fair amount of blood and gore within the battle scenes, and the colour toning and mood feels similar (the use of oranges and sunset colours). Both shows like to go into detail about the strategies used in some of the battles and spends a lot of time on them. Both also feature a short 'training arc' and then goes straight into the action on the front lines. Both shows also have a 'sister-type' figure who is very strong and skilled
+Overpowered, Overprotective sister figure
+The hero party joins a military organization
+The protagonist plays a pivotal role in the success of battles and isn't just a pawn
+The protagonist has ties to scientific figures
-"Alderamin on the Sky" lacks the oppressive atmosphere of "Attack on Titan". In fact, the power balance is in reverse with respect to the protagonist's side.