Now some here might not be knowing what Kingdom is so I'll briefly explain : It's a manga set in the ancient Warring States Era period of Ancient China during which seven states waged innumerous wars against each other for 500 continuous years in hopes of gaining land, riches or prosperity in general. Now, our protagonist, Shin (or if we go by his historical Chinese name, Li Xin) was a slave boy who dreamed of being the greatest general under the heavens alongside his childhood friend. However after his friend's death at the hands of an assassin, Shin encounters the King of Qin, Ei Sei (one of the seven states), whose aim is to unify China into one single empire after half a millennium of strife and carnage. And that's what they aim to do, alongside several other notable and loveable characters like Mouten, Kyoukai, Karyo Ten etc.
Now
hold. I'm pretty sure that Kingdom, from my summary is giving you a rather cliche vibe and unoriginal idea. However, Kingdom is easily one of the best series out there imo. True, the first 100 chapters are so-so and have a very shonen-esque feeling to them but once the Bayou arc starts, that's where it hits gold and hardly is the consistency let down. The conquest of China is hardly anything like just a stroll in the park like it usually is with the goals of several other MCs, the author makes it quite clear the path needs to be paved with iron and blood. From Bayou onwards, there occur many deeper themes like betrayal, questions of faith and trust, the horrors of war such as murder, pillage and rape, the good and evil ambitions of men, camaraderie and friendship which gives it a really good dual vibe, heartfelt romance between certain characters that aren't cringey like 90% of the time. It's also morally grey so if that's your style, then Kingdom will fit the bill right in.
The characters, on top of several being total badass motherfuckers, are really complex and well-written. Shin's growth, for example, throughout the series is organically reproduced and there are some heavily developed characters like Ouki, Kyoukai etc and others with a great deal of moral depth like Riboku or Kanki, on top of having great dialogues,Zero characterization and tons of hype moments that'll get your adrenaline rushing to boot. Each of them feel extremely natural ( at least after the first 100 or so chapters) and it is an extremely diverse cast, ranging from many types of characters.
Now the setting is also very unique. There aren't many manga out there that depicts what Ancient China was truly like. It's accurate right from the architecture of the buildings and the palaces right down to the scenery. The author had even visited China's ruins to portray this feeling of ancient wonder from the art itself.
Now comes the battles, wars and strategies in Kingdom. I think many would agree this is one of the strongest aspects of the manga. The wars are always unique, impactful and in large scale that most other manga fail to show. Just because one army's soldiers or veterans or generals are stronger than the other's doesn't mean it's an automatic win. No, there are several intriguing and mind-blowing strategema and tactics used several times throughout the series. Examples of such would be grinding down an enemy charging unit from it's right and left flanks or using psychological attacks to instill fear within the soldier or using the surroundings for an advantage and so on. Even the solo fights implement these and they're always well-choreographed, as you can feel each and every blow and movement plus several unique style of fighting are used. The fights also tend to be very emotionally heavy so be prepared for a roller coaster of feels as well. Not to mention, the wars aren't done just for the sake of showing wars and neither is the gore and darker aspects shown just to act edgy but rather each war has a meaningful impact and reason within the overarching plot.
Also keep in mind that Kingdom has been keeping this level of consistency for over 430 chapters and it's confirmed to go above a 1000 so you can expect even more legendary content.
If you're still not convinced, here's some great art that can make you bend your knee :P :
Beware of spoilers!
I haven't read Akame ga Kill manga so I can't say anything about it but hope you consider voting for Kingdom. :3
P.S : If you do consider getting into it, don't watch the anime. It's garbo.