@Akari20:
Liselotte has the same skill as all of the other Gold+ soldiers, except for Altair and Jake. She's good skill-up food that is worth farming.
To make things fair, Liselotte has a mincost of 13, so she's only as good as a -1 Jerome, except Jerome has a +2 initial cost buff when you start a map, so his 13-14 cost only means you have to wait 1-2 seconds to deploy him on a 10 initial cost map. Jerome's biggest competitor is a mincost Aria (she's the easiest soldier to mincost), and Aria is theoretically superior to Jerome on maps that start with 10 cost until you cost reduce him a little bit. Jerome's biggest benefit is that his AW skill is automatic, so you won't waste any real-life time pressing buttons, and any time gained from Aria would require super-human precision. Jerome and Julian are the best soldiers because of this, since most of your time is spent farming maps, so characters with auto skills are the most-convenient.
The reason you may want Liselotte regardless of all of this is her ability; if you want your heavy armour units to have the necessary defence to tank the worst physical foes this game has to offer, then you're going to need Liselotte on your team (she'll also buff Altair so she can tank foes more easily with her skills). Katie's +2 def will stack with this, so Liselotte+Katie means your heavy armour tank will have +7% defence, which can be buffed further with characters like Princess Louise, Rear Tactician Lian and Spirit of War Cynthia.
Altair's ability gives auto-retreat for soldiers while she's deployed, which means you can treat your other soldiers like sacrificial pawns if you have characters that can give them nullification and evasion (i.e. Leona and Sarasa) without worrying about losing a star if they fail.
EDIT:
Just to give concrete examples. Soldiers that synergise well with Altair are the Silver Soldier Rosalie, and the Plat Soldier Jake (yes, you used him as skill-up food, but he's actually better as her faithful lackey). Rosalie has a skill that gives her 50% evasion for a long duration, and Jake has a regular skill that counters physical damage with 1/2 true damage. If you had Jake tank Furfur while Leona's buffing him with damage nullification, each time LV15 Furfur fails to kill Jake means it will receive 8050 true damage. Furfur has a decent attack speed, so if you're lucky, Furfur will deal a substantial amount of damage to itself against Jake.
