Heavy Object

Both shows involve regular army soldiers going up against bigger and better opponents and succeeding using intelligence and quick thinking. Both also have a bit of a geo-political vibe to them. 

Advanced weaponry that looks possible in the near future, a cast of characters that are both comedic and serious at times and don't forget the great chemistry between them in their respective series. In my humble opinion, if you enjoy one series, then you will definitely find enjoyment in the other! 

Both main characters try to make a new type of super weapon. While Heavy Object focuses more on war with other humans+objects, Knights and Magic is more fantasy themed as in fighting monsters with the help of magic. Heavy Object also has more romance and humor in my opinion. 

Same author, same studio. The MCs are both anomalies within the futuristic world who repeatedly go up against enemies that logically they should have no chance of beating, but come out on top anyway with a combination of determination and quick thinking, though the way Qwenthur takes down Objects is more in line with how Shiage from season 3 of "Index" defeats his opponents (they even look similar). They also have several of the same voice actors- Touma and Havia are voiced by Micah Solusod, Index and Oh-ho-ho are voiced by Monica Rial, Hyouka and Milinda are voiced by Alexis Tipton and Kanzaki and Froylatia are voiced by Shizuka Ito and Morgan Garrett. However, "A Certain Magical Index" is better in just about every possible way. read more 

Both of the show got robot fight and strategies in it. Code Geass is about a man want to create peace in the world using a certain supernatural power called "geass" in a world where robot exist. Heavy Object is about a certain infantryman fighting robot called "object" using their briliant strategies. 

The heroines of these series are extremely similar in both their personalities and their outlooks on life. Mikan and Sakura are both elementary-school girls who find their school life difficult because of their crazy classes, especially one troublemaking boy. They succeed in solving their problems using their optimism, never-give-up attittues, and unique skills 

If you're a mecha fan, than you have to see Gurren Lagann - one of the greatest mecha series of all time (along with Evangelion). 

Although deca-dence has more of a mobile fortress feel to it it reminds me so much of the gigantic mecha's used in heavy object and how these things do battle with other similarly gigantic things. As well as how just single people can also take down these gigantic things which is present in both.  

Similar situation where MC is genius at tactics but doesn't necessarily want accolades that are awarded. They both deal with MC who is not physically suited to battle but intellectually superior to all opponents. Also cares greatly for human life. Heavy object has more of the humorous and ecchi moments we all love.  

Both has main character defeating mecha in flesh i.e. without being in one as they come up with clever ways to defeat mecha-of-the-week. 

Both have awesome cast...Havia/Irisdina best team combo ever.... Both has gigantic war machines [ in Schwarzesmarken ~ Mecha's & in Heavy Object - Objects [ I love them so much :) ] Deaths, betrayals...secret services... logical and technologically advanced war... Both have likeable protagonists [Havia/Qwentur & Irisdina/Theodor...] Both are trully underrated gems... 

Idiotic and perveted male MCs are going in battles. Both shows have some kind of militaristic theme, doing missions, wars etc. 

Hey guys this is my first recommendation actually what i find out that Heavy Object had no dark background as M3 does but in Heavy Object u get a mecha that has only big guns and spherical body while in M3 the mecha is just like a transformable giant egg w/ many weapons and only operable in the "lightless realm" and in Heavy Object u get 2 guys do the demolition job in any mission while in M3 they don't had it if u want to drop M3 from ur anime list why not try to watch Heavy Object and i know you will forget M3 someday (note: only to the M3 watchers) read more 

It involves two guys who gets to do all the dirty work for the team, while the girls are confined in the comfort at the base, the differences, Heavy Object was more of military, while Active Raid were more of police genre