Halo Wars is a real-time strategy game from Microsoft and Ensemble Studios, and it first hit the Xbox 360 in 2009. The game was largely well-received, though development was rocky and it ended up being Ensemble Studios' final title. Ensemble founder Tony Goodman said in 2012 that the game wasn't originally Halo-themed, but Microsoft thought it would perform better if it carried a recognizable name. Plus, Bungie, the studio that created Halo, was never into the idea of Halo Wars, Goodman said.
Current Halo developer 343 Industries and Alien: Isolation studio Creative Assembly are working on Halo Wars 2 for Xbox One and Windows 10. Last we heard, that one was due in fall 2016.
That's enough about Halo.
Soul Calibur 2 is an immensely popular fighting game that debuted on consoles in 2003, and an HD version landed on PlayStation 3 and Xbox 360 in 2013. That's the version hitting Xbox One's backwards compatibility lineup today: Soul Calibur 2 HD Online. The King of Fighters '98: Ultimate Match is a remake of the original 1998 KOF '98 game; it came out in North America in 2009.