[Update]: Total War Troy's next DLC expansion is adding two new factions led by Rhesus and Memnon.
It may have taken quite a while, but Total War: Troy's Epic Games Store exclusivity has come to an end and so Troy has now made its way over to Steam as well. More importantly, it has done so alongside the release of a long awaited new expansion - Mythos!
As the name would suggest, the Mythos expansion brings with it a whole assortment of mythological monsters and themed units to play around with, thus fixing one of the biggest complaints many have had with Troy since the very beginning. Besides the monstrous menagerie, Mythos has also updated the world map with a variety of references to classic literature and legends, as well as added army-wide abilities granted by the gods themselves.
You can get a bit of an idea of what all of this looks like in proper gameplay, as well as check out which monsters you'll be able to capture and utilize in battle, through the recently posted trailer. Have a gander:
As for whether it's actually worth grabbing the new €25 Mythos expansion, that is a difficult question to answer. From what I can tell the Mythos expansion is exactly what Troy was lacking all along, yet the high price tag makes it hard to recommend given that you can grab the infinitely more monstrous Total War: Warhammer 2 for that kind of money during its numerous sales.
In the end, I think this decision will depend entirely on how much you love the setting. If you're a massive fan of Greek myths then the expansion might just be worth grabbing because of that, even at its somewhat inflated price point. On the other hand, if you're just here for the giant monsters, then I'd recommend simply waiting for Total War: Warhammer 2 to go back on sale. It's bound to happen sooner rather than later given that Total War: Warhammer 3's big release date reveal is fast approaching.
Whatever your choice may be, you can read more about the Mythos expansion, as well as check out some user reviews, over at Mythos' Steam page. Have fun!