In a similar vein to the previous Ys thread this topic will focus on Falcom's other major franchise the Trails of series. This consists of three main storylines the Trails in the Sky arc. The second arc is the Crossbell series which is made up two games which are Zero no Kiseki and Ao no Kiseki. The next arc is Trails of Cold Steel which consists of four games. There are games after Cold Steel, one is Hajimari no Kiseki and from my understanding it is a transitionary game between the Cold Steel series and the new subsequent arc. The latest game which is due to for release in Japan is Kuro no Kiseki.
Unlike Ys, these games are connected and whilst new fans can start on each arc without worrying about the previous games that went before it, it is recommended that if you do start a game you either start from the first game in a given arc rather than bang in the middle. If for example you start on Cold Steel 2 not only only will you be spoiled but there will be parts of the story you won't get as it was covered in the previous game.
Some hardcore fans will insist you need to start at the beginning but I don't think Trails in the Sky is required playing for Crossbell or the Cold Steel series. Saying that if you want to understand everything it is best to play all the games in chronological order. I will note the link between the Crossbell and Cold Steel is stronger than Trails in the Sky (although it should be noted Trails in the Sky does foreshadow events in Cold Steel IV). If all this sounds confusing just either post in this thread or send me a pm. The games are real good so I recommend playing them all but just be sure to stock up on Redbulls and coffee it is an enjoyable but loooong ride.
Here is the order you should play if you want to go into this mad journey:
Trails of the Sky Arc - (Estelle, Joshua and Kevin as the main protagonists)
1- Trails in the Sky part 1
2 - Trails in the Sky part 2
3 - Trails in the Sky part 3
Crossbell Arc - (Lloyd as the main protagonist)
4 - Zero no Kiseki (Trails of Zero)
5 - Ao no Kiseki (Trails of Azure)
Cold Steel Arc - (Rean as the main protagonist)
6 - Trails of Cold Steel 1
7 - Trails of Cold Steel 2
Note: Events in Crossbell and the first two Cold Steel games cover a very small time window with some scenes actually overlaping between the games meaning you could play Cold Steel 1 and 2 then jump onto Crossbell or vice-versa.
8 - Trails of Cold Steel 3
9 - Trails of Cold Steel 4
10 - Hajimari no Kiseki (Trails into Reverie)
11 - Kuro no Kiseki