Get Sara first. Hallessena needs people to protect her, and MC on Holy Saber alone will have a rough time with that when you're also lacking buffs/debuffs. Judging from your other topic, you're probably still married to Dark Fencer for the time being, which is great for Sara since gravity+slow get you a lot more mileage out of her skill set.
Not sure if any of the mods still support this community, but they should be aware that the forums are infested with bots and that their forum needs to be upgraded.