Reached level 18 and obtained another skill.
It’s anti-guard stun. With this, she has anti-stun for every move (Attack, Break, Guard). In my memory of the first game, using her is more exciting than say Saber, who just needs to attack and attack. Archer is also pretty interesting because you need to strengthen yourself during battle to be more powerful and have access to more skills, but that seems to be self-imposed weakness ^^;
Caster is mostly about stunning the opponents with her magic. I don’t think she’s going to have anti-skill stun, but the master can have that skill by wearing certain equipment. Pretty much the only thing holding her back is the limited resources of MP. Using her can be very exciting.
You may also notice my master is wearing a gym outfit. That’s the gift from having a save data of the first game when you first start the game. You can only change after the servant gains the first game’s original outfit in chapter 2, which unlocks the closet feature.