Which servant should i pick?

between salter,sabelot(np2),lalter,nito and yagyu(np3) who should i pick?
i already have support like merlin,tama and casgil

IMHO

Salter: at this stage of the game she’s not as strong as she used to be, tho from all the 4 star sabers she is still the best for farming lancer/berserker mobs. A good pick if you like her badass animations and hypnotizing smug, but that’s it.

Saberlot: His power comes from his skills, not his NP. I don’t really see that much of an improvement in upgrading his NP.

Lalter: Farming beast for everything except saber mobs. A great pick.

Nito: The queen of farming. Her insta death np is a big quality of life improvement. tho not that good doing anything else.

Yagyu: He’s amazing but NP3 Yagyu is really overkill. Not saying it’s a bad choice but you better use that ticket somewhere else.

So either Lalter or Nito. Both are excellent farming servants, and since you have Merlin and Tama then it’s just a matter of your personal preference on which you like better.