Skadi is out of this as I can’t get the materials, so I’m choosing between Enkidu, Altera, Anastasia and Osakabehime
Euryale If you can help it.
I’d raise the Servants you like the best, because you can get pretty damned far on borrowed Servants even at that point.
Euryale does deserve a shout-out here, being a great option if you also happen to like her.
Level up your Tristan and your Chiron. There’s an infamous Saber boss whose passive allows him to quickly charge his NP. Emiya greatly benefits from Chiron’s 3rd skill
Keep levelling your Hime. She’ll become a defensive powerhouse alongside your Mash (She gets a ton of upgrades in this singularity)
Next, level up your Attila and your Siegfried, as the final boss is weak to these two
Siegfried for some dragon busting. This one of the few times he was made for a fight,
Euryale then David, then Mash. Euryale in this singularity will do a lot of the heavy lifting, David has his excellent utility with a party wide evade, Mash is a very tanky servant. Alternative to David Tristan is also an option.
After that whoever you like, I would recommend Enkidu since he’s a good soloer overall but nothing particular on Camelot requires him. Also if I’m not wrong Anastasia needs frost from LB 1 so unless you have some from events you aren’t going to be able to raise her. Neet hime deserves a mention too, since she can provide support and heal. Chiron also does that support thing but he needs gunpowder again from LB 1.
Euryale, David, Tristan, Mozart and George are good starts.
Sieg will be useful later on the story if you have him at NP5 (and raise Paracelsus), Chiron is a great semi support but his damage isn’t the greatest, post rank ups EMIYA is one of the most versatole servants in the game and yours is 4th ascension so i recommend you use him, after Camelot you will get a Story locked ST Saber that you should level.
Skadi is great but her ascension and skill materials are locked behind Part 2 chapters. She needs to be 10/1/10 minimum to make the most out of her. Similar issues aflict Anastasia, also her damage compared to Sieg’s, without her battery maxed she isn’t very good especially at NP1
I think I’ll go for Euryale since she is cheap and great against the Camelot boys, then probably tristan/enkidu
Mash, Andersen for every stages
Euryale to counter Garwain. Especially we rarely find powerful Euryale in friend list.
David to counter Mordred, Garwain NP
Arash to counter 3 high HP knights stages
Siegfried is useful too, high dmg to final boss