Kohan series
There's 2 games, well, 3 if you count the fact that the first game expansion, Ahriman's Gift, is a standalone one. But they are RTS games that I don't see any other RTS copy much of it.
I'm saying that because of how the game works. Instead of recruiting units, you create a company that's basically a collection of units, having at minimum a frontline of 4 basic units of the same type (could be infantry, archers...), but you can create bigger companies with additional 2 support units that range from healers, mages, tougher warriors like paladins, summoners that conjure temporary units, or even other basic units (but only in the first game), and a rearline of 2 basic units. (but this only in the second game)
Company structure can be very important. It's creation is instantaneous, but you only have it's captain, that's usually a generic unit without any noteworthy skills, ready to go. It may need to wait near one of your cities/forts to fill/refill/heal it's ranks, so the shorter the company, the faster it will be at full capacity. Also, certain basic/support units can give a bonus to the whole company (like more defense or vision range) as long as you have at least one alive, and while you can have cavalry and infantry in the same company, it's regular speed will always be equal to the slowest unit. Some things to keep in mind when creating companies, aside from upkeep and formation.
Speaking of upkeep, economy and resources works differently in this game. You have five: Gold, Stone, Wood, Iron, and Khaldunite (which are magic crystals). Gold is the only resource that stockpiles, and you spend it a lot in buildings and companies. The other resources act as a sort of cap/limit of upkeep for certain individual units (for example: archers require wood, and the more mystical units require khaldunite), and you can recruit units even when you don't have these resources, BUT doing so will affect negatively your gold income depending of the resource, and trust me, having a negative gold income is a slow death to your army. (literally, your units will start to slowly lose health if you have zero gold and a negative income)
Building is a little different for a RTS because it's closer to a 4X game. You just have a city that has a passive gold income with many slots for buildings to generate more gold and/or other resources and allow certains units/companies to be created, and it can also spawn militia to defend itself. You can also create pioneers to build new cities.
Also we have the Kohans, which are the hero units of this game. They can replace the generic captain and they range from warriors to spell casters, and they can grow stronger. They can be revived if they are killed, but they will lose all the XP they gained.
The story is meh though. It's your typical good vs evil fantasy story where you face evil Kohan (the Ceyah, as they are called) that commands armies of undead and demons (and also some mercenaries). The second game I can say they try to spice things up a little, they even have one of the evil Kohans from the previous game going to the heroes side (although he behaves for the most part like a huge edgelord, but I've seen worse), but even so I felt the plot was a missed opportunity. But I want Ross to judge that part for himself.