Who should I spend the resources on? Will an Np 5 Chloe completely outshine Arjuna, or does the 5th star make the difference?
That depends on what you need them for since they fill two different roles in a fight.
Chloe is an ace boss killer due to her easy NP5 and her Single Target NP. Arjuna has an AoE NP which has a chance to cause instant death, making him a better farmer and wave clearer.
Statwise, Arjuna has Chloe beat, having higher HP and ATK. Even if you bring Chloe up to level 90 using Grails, her stats still won't be equal to Arjuna's.
If you need an Archer DPS for bosses or high-level enemies, use Kuro. NP5 really makes her NP hit hard.
Instant death is largely inconsistent, much less with Divine foes, but Arjuna boasts higher base damage and health on normal attacks. Use him for farming, because normal mobs are more likely to die from Instant Death and flat AoE damage
I think my farm game is covered at this point, and raising up an SSR just for that seems pretty wasteful. Chloe it is.
Chloe is very different from Arjuna, but Arjuna is bad overall.
He is a worse version of EMIYA, he has a weaker version of Mana Burst that is only better when using the NP. He has Clairvoiyance, a terrible skill and he has a charging skill mixed with innocent monster that has a high cooldown.
His NP relies on Instant Death, which is unreliable and he has no survivability whatsoever. Emiya, Atalanta and Tesla are all better than him either because they have solved his problems or are cheaper
So if I find myself in desperate need of an aoe archer I should level Emiya then? Despite my best efforts, I've got that guy at np 4.
Also I guess I should have mentioned that I've already got an np2 Squirtgun Arturia nearly maxed. Just wondering what do with the spare gems.
EMIYA is a very good AoE Archer but he is normally a secondary DPS since his attack is not the best, his 2nd and 3rd skill are amazing and he is very easy to use and since you have him NP4 he can deal a lot of damage with UBW.
