Fire Emblem: Three Houses is finally out, and we've got the rundown on how to start filching students from your competing houses. When starting up Fire Emblem: Three Houses, players will be tasked with joining the Officers Academy as a professor and tasked with leading one of three Houses (hence the name.)
Before making your final pick between the Golden Deer, the Blue Lions and the Black Eagles, you'll be shown the students in each house. These are the students that come pre-packaged with that playthrough, and you're stuck with them. If you've got a student that won't stop grating on your nerves and talking about his noblesse oblige, there aren't many options other than simply not using them. Or, y'know, letting them die in battle, if you're that kind of professor.
However, as you start roaming the halls of the Officer's Academy and talking to other students, you'll meet the class members of your opposing houses. Without spoiling anything, these will also be your potential enemies should things go south down the road. The Officer's Academy contains students from all over the land, after all, and if war breaks out their loyalties will be questionable. Luckily, you can befriend these students and if they like you enough, they might request to be in your class before things go sideways. There's also always the "recruit" option if you think you can convince them personally.
To get students to start liking you, however, you're going to need to sacrifice whatever build you're working on for your character. That means if there's a cute red-headed mage girl roaming the hall every day and you want her on your side, she's not going to be impressed by your thief with amazing axe skills. On the other hand, once you re-class into a mage and level up your Reason stat, the warriors students of the Officers Academy will let you know that you'll need more "brawling" or "axe" proficiency before they're comfortable enough to request a transfer. Recruiting all students from other Houses is therefore impossible - simply focus on one or two at a time to spend time with to make an impact.
The best solution, then, is to train your protagonist in several areas. Even if you're not focused on a mage-build class, there's always the option of training with other professors in Reason or Faith to level up that stat while your thief character focuses on his axe skills to recruit that axe-loving monster from, say, the Black Eagles. However, this will be a much slower process than simply using magic in battle as a mage. In addition, on higher difficulties, battles will become scarcer, and that means less enemies to level up your skills.
Most of the skills Byleth can focus on are pretty straight-forward. If your character uses Axes, their Axe skill will level up. The same goes with a Lance, Sword, Fists (for Brawl) or Bow. However, when trying to recruit students who tell you they're not comfortable with you yet, you'll probably get a message saying "Cha" needs to be higher, and have no idea what to do to increase that stat (or what it is.)
That stat is Charm, and along with Authority, Riding, Heavy Armor and Flying, it's a stat that won't be trained by simply heading off to battle. Faith and Reason are confusing simply because of how they're worded - Faith is white magic and Reason is black magic. The final stats can be raised by training with the professors of the school grounds. Look for Priest professors to level up Faith, for example, and Knight professors for Heavy Armor. Charm only levels up by hosting Tea Parties, an event that happens naturally via a quest.
These tea parties carry their own difficulties as you'll need to pick the right conversation topics with each character you invite to get a "perfect teatime." It's good to keep a save before inviting someone to tea, because choosing 1 out of 3 correct options 4 times becomes a headache if you don't know a character inside and out.
Group activities can be assigned during lectures and focus on stats you don't normally get otherwise, such as flying and heavy armor. Attending another professor's lecture will also train you and your students in that professor's proficiency.
Finally, there are certain items you can obtain on the battlefield which will automatically level up Byleth's stats. It's best to use these on Byleth rather than one of your classmates.
With that, you should be well on your way to amassing an army of students from all walks of life to crush this mammoth of a game. With over 200 hours of content, get used to the feedback loop - it will become your life.