Both have their strength and weaknesses. Fujino in terms of solo play has the better kit for surviving I’d say than Emiyalter but not by too much. They both have defense that shines in different areas better than the other but for the 2 descriptions I’m giving for both characters based on me playing them, I’m going to go in a solo perspective.
Emiyalter’s defense/damage cut combo can tank NPs quite really well as well as minimizing a lot of normal attacks, but due to it being only 3 attacks instead of turns, its only going to last maybe 1 1/2 - 2 turns at most but what he does defend against basically makes the hits null.
Fujinos however has no defense boost, but has a damage cut 4x higher than Emiyalter so most normal attacks enemies do basically deal little to no damage. Problem is when it comes to an NP, she is…basically screwed. She’ll survive because she has guts but it’s only 1 time and gives 1 HP so you basically have 1 turn left and that’s it. You’re most likely not going to have max HP anyway in a solo fight, so the HP cap reduction isn’t too much of a negative to me. One of her positives she has for her survivability however is her NP effects, as 10% damage debuff combined with her damage cut allows her to tank even more damage along with her eliminating the enemy from activating a buff which could help keep them from buffing their damage, crit chance or other things that would really be a problem for her specialized type of defense.
If we’re speaking of in general, Emiyalters greatest strength with his defense is that you have the chance to have defense consistently. His defense/damage cut lasts 3 hits for 5 turns on a 5 turn cooldown, which allows him to potentially keep his buffs the entire time until the next activation if the enemies space out attacks to him in the allotted time compared to Fujino having 2 turns of no defense at all.
But that’s just my 2 cents. If someone else who uses these servants a lot more than me (I mainly use Tomoe for my ST Archer) and feels I wrote something off or completely wrong, lemme know.