Final Fantasy XV: Episode Ardyn - Prologue

Both share the same art style and provide further insight//lore to the world of FF XV. Whereas Brotherhood gives us some back story on the 4 protagonists of the game, Episode Ardyn gives us some well needed back story to the main antagonist of the game. Fans of Final Fantasy XV are sure to enjoy both. 

Both and essentially short animated promotions for the FF XV game, although the Kingsglaive ONA is also promoting the prequel movie "Kingsglaive: Final Fantasy XV" and the Episode Ardyn Prologue is promotion for specific DLC for the game. They still target the same demographic and fans of the game will find some enjoyment in both. 

Both provide additional lore to mainline final fantasy worlds. On the Way to a smile focuses on a side character of 7 Denzel whereas Episode Ardyn gives extra back story to 15's main villain and the series namesake Ardyn Izunia. Both series will appeal to the exact same audience, FF fans who appreciate additional anime content. 

Both beautifully animated and give further story to popular and current Final Fantasy games. Advent Children Complete is the definitive sequel to the fan favourite VII which has its long anticipated remake approaching whereas Episode Ardyn is a prequel to the most recent mainline title XV and gives backstory to that titles most prominent villain. 

Both provide additional back story to mainline Final Fantasy games. Both expand on the story of the series' main villains Sephiroth & Ardyn. Fans of the games/series are very likely to enjoy both of these anime. 

These are both animated Final Fantasy specials that give additional insight into mainline FF titles. Final Fantasy (OVA) delves deeper into the story of Final Fantasy V whereas Episode Ardyn delves into the character back story of Final Fantasy XV's main villain Ardyn Izunia.  

Both these anime provide additional lore to Final Fantasy games. Advent Children works as a direct sequel to the fan favourite FF7 whereas Episode Ardyn is a prequel to the more recent FF15 which shows the backstory of the series main villain. Fans of Final Fantasy or either game will enjoy both.