I'm usually a lurker here on the site, but when I saw
Party of One: Jan in the Sky with Trails
I couldn't help myself.
So, as someone that's been playing and enjoying the games since the original US PSP release back in 2011 I wanted to make myself available to anyone who wants to know more about the series. As well as a place for other "Kiseki" nuts to gush and answer questions here. The first two games in the series, which are literally just one game split into two, are my favorite games of all time. So much so, that I worked with another fan to create English patches for the Sky Evolution vita games that were never brought over here (Sky FC Evo, Sky SC Evo, 3rd Evo).
I also plan on giving out copies/PC keys of Trails in the Sky in chat during Jan's stream, so ;) look forward to that if you want a chance to jump in for free.
For a spoiler free generalized introduction to what the "Trails" series is I highly recommend this video from KillScottKill on YouTube (disclaimer, I'm a patron of Scott's):
As for where to start the series I would recommend his follow up video:
They are older videos, since Cold Steel 3 has come out since then and Cold Steel 4 has been announced for release this year (on PS4, PC/Switch will be released in 2021), but they are still very good intros. I'll echo his advice that I recommend you play the original Trails in the Sky first, but won't fault anyone for wanting to try out Trails of Cold Steel first instead since it does have a lot of quality of life improvements over sky. Just, please, PLEASE for the love of video games don't start with Cold Steel 3 (yes, I know it's the only one on or coming to Switch any time soon, I'm sorry).
Now, I do have a couple of warnings for those of you starting or considering the series. Trails in the Sky is a slow burn (even by JRPG standards), and is meant to serve as generalized world and character introductions, but if you make it through and aren't too mad at its MASSIVE cliffhanger (RIP me circa 2011, I had to wait until 2015 to get a resolution to that massive bombshell), TitS SC makes up for it. This is alleviated somewhat by the fact that XSEED patched in a turbo mode into the trilogy a while back that speeds up combat and exploration in the PC version, but it's still worth knowing going in. My other piece of advice/warning I want emphasize that tthe Trails games are games that reward investment, for example, all of the NPCs in the Sky trilogy are named (some even come back in Cold Steel) and will change their dialogue after every story event. Not after every major story event. They update after story event and many of them have mini internal subplots that start in one game and are paid of in a later one. This extends to NPCs that are ridiculously out of the way. Take your time, enjoy the scenery and Trails will reward you for it.
I could easily keep going, but I'll leave it there. Oh, and I recommend tracking down the Evo voice mods for the PC version if you have the gumption, I won't link out to anything here since I'm one of the crazies that has access to dumping the JP voices from the Vita games on my own, but it is out there and it does help the game. As I mentioned earlier Sky and Sky SC are my favorite games of all time (as a duology--3rd is an extra/"gaiden" game that's sort of its own thing), but not because they do anything in particular new or exciting on its own. They are my favorite games of all time because of how well executed they are as JRPGs, so I wouldn't go in expecting anything to subvert your expectations.