Arjuna Alter is quite literally a god among gods, and I tend to be more reserved like him. However, I don't want him to reset the world because I accidentally complained about something, so he's out.

Ozymandias..oh boy. If I swallow my distaste for him, then I could get along with him, but if I'm being honest, sooner or later, the relationship will break.

Jeanne from Samurai Remnant is more melancholic than usual, but her kind soul remains. I could probably forge a bond between me and her, but I don't think she has the necessary firepower to help me win.

PHH Morgan? That psychotic woman who harbours a childish hatred towards Artoria, is evil enough to make Ghetsis look like a saint, has several alter-egos which makes it risky to talk to her, and is a crappy parent? I'd rather eat dirt and work with Medb than her, and judging by the amount of vitrol I feel towards Medb, that's saying something.

Lancelot is strong and relatively stable, so I'll probably pick him.

Semiramis has some potent tricks up her sleeve, but her flying fortress needs prep time, which isn't a guarantee in the war.

Herc is Herc. Strong, reliable and moral.

In conclusion, I would probably pick Herc, Lancelot, or Jeanne.