Opinions on my strategy for Ch.18 boss fight

Well, if you got through the Chapter 17 fight then this should be easier. Especially since you have Xuanzang from friend support. And your team is pretty good actually. Just be sure to take out Enigma ASAP. Without it, Moriarty isn't all that different from the last fight.

Your party will get 20% NP charge at the start of each turn during the whole fight (but sometimes Enigma will remove 20% from the whole party or 100% from one Servant). With Tamamo Caster's NP and Xuanzang's NP Battery, you may be able to fire off 2 or 3 of her NPs before a second NP from Enigma.

You'll want to pray to RNG since Enigma has a skill that charges 3 NP bars for an ally. And since Moriarty only needs 3, he could end up firing his NP back to back if you're unlucky.

But once Enigma goes down, you're pretty much set. Just keep Tamamo alive as your healer, and Mash as well to draw off his NP whenever possible.

For me I take out the Prof fast and quick before focusing on the ghost. Since most of support is Caster class, the ghost won't hit them as hard as Moriarty after taking out Prof Moriarty just switch to Xuanzang and spam NP to kill the ghost fast, hard and quick.

Mashu + Scathach + Merlin = Chapter 17 - 18 ez win.
Battles ended with almost full hp, no switching up and no casualties.
No wonder I got 150 friend points today on Lancer.

chapter 17 focus fire Moriarty.
chapter 18 kill ghost first bcoz the debuffs will cost ur life.

i did a similar strategy, but i runned merlin (support) mash and sanzang, and jaguar warrior in the back line. and anniversary blonde instead of atlas.
i focused enigma with sanzang ulti spam, used mash to tank the first np with inv and tount, then let the second kill sanzang so taiga could come in and slaughter him.

I ran Robin/Tamamo/Mash and had no issues. Robin can burst down the demon pillar and the Assassin before they can even NP and Mash + Tamamo can stall out Moriarty in the meantime.

Then I swapped Robin for a lancer (Enkidu, in my case) and it was a typical vs. Moriarty fight. You have Lancer Vlad and Tamalancer so you’ll be fine.

Use Tamamo Lancer and have a Merlin support her, better yet two Merlins. Tamamo's np multiplier + her np regen makes her amazing against males archers with break bars.