Craft Essence time!
5*, Origin Bullet: Pierce Invincibility, +35% damage to Caster enemies
I still find it odd for Assassins to be weak to Casters, especially since Kiritsugu is on this one. Really cool art, though!
4*, Covering Fire: +400 damage, +15% crit damage
Not much to say about this one. Worth keeping around if you get it, since a lot of future challenge quests give enemies really high defense, which the flat 400 just ignores.
3*, Battle of Camlann: 10% party NP charge on death
Good if you want to do solo quests. Put it on a level 1 George for free charge.
WARNING, SPOILERS FOR MAJOR BATTLES AHEAD
So, first up is the real boss of Camelot: The desert. Will murder your phone if it's a potato. Can confirm, used to have potato phone for playing FGO. Just a warning that your stuff might experience major slowdown and/or game crash during this chapter. Babylon isn't nearly as hard on phones as Camelot.
For real bosses though, Gawain is our first contender. He appears in Chapter 4 (Arrows 4-5) and 17-4 (Arrow 2).
His first appearance he will not use his NP, instead using his extra attack. However, as a tradeoff, he takes 20% damage rather than 50%. This one you just have to take off a quarter of his health, so get it below 279,564 to win. The second battle and beyond he WILL use his NP and you DO have to fully kill him. Also note, he will use any of his 3 skills, including his NP charge skill. During all battles he gains 2 ticks of NP charge per turn. Bring Euryale and/or Orion.
Mordred is the next boss we'll see, in Chapter 7 (arrows 3-4) and Chapter 17-3 (Arrow 1).
She WILL fire off her NP at the start of each of her turns unless you stun her, drain her charge, or kill her. In Ch 7 Arrow 4 you fight her twice; however, the first battle she will only use her Extra attack instead of her NP. Either bring hard-hitting Archers to take her down fast, or take Asterios to remove all her damage and get free NP charge.
Then we have Tristan, who just breaks the class triangle. He's in Chapter 12 (Arrows 3-4) and 17-3 (Arrow 2).
Yes, he's an Archer. Yes, he's weak to Sabers. Mashu is the only one who remains normal to his bullshit. He acts like a Berserker, AKA 1.5x damage to everything except Ruler/Mashu. Those take normal (1.0x) damage from him. At the very least, his attacks will recharge YOUR NP super fast. Bring Sabers for more damage.
Finally we have Lancelot. 13-3 Arrow 1 and 15-1 Arrow 1.
Lancelot is immune to debuffs and acts like a Ruler in that he takes half damage from anything except Berserkers, Rulers, and Avengers. He DOES, however, only deal half damage to Archers and Rulers. He'll target whoever has the most HP with his normal attacks, but not his NP. Get out yer Jalters for this.
Finally we come to the last bit of information. Mashu gits gud. Really gud.
Spoiler
Chapter 15 Arrow 1 turns her into a 4* and gives her third ascension. Her first skill also gets an upgrade, increasing the defense boost and giving a one-time 2000 damage cut.
Clearing Chapter 17-4 upgrades her NP into Lord Camelot, adding a 30% attack buff for non-Mashu party members and getting her to NP2 for a higher base damage cut.
