There are various weapons for Cloud and company to equip in Final Fantasy VII Remake, and a few are earned by completing some of the many side quests found in the game. Aerith’s Arcane Scepter is one such weapon, and you’ll need to reach Wall Market if you aim to grab it.
The Arcane Scepter is rewarded from Shears’ Counterattack in Chapter 9.
In Chapter 9 you’ll eventually leave Aerith with Madame M, and during this time a handful of side quests will become available. Shears’ Counterattack isn’t immediately available, so you have to complete the first two side quests to unlock it.
Burning Thighs is as simple as winning the squating minigame once, and The Price of Thievery has you taking down a familiar bandit gang solo (though they have added a grappling menace to their squad). These are simple two-stage quests, so it won’t take you long to complete them.
Once they are out of the way head back to Madame M’s, where you’ll be accosted by the arena announcer before entering the massage parlor. Accept the Shears’ Counterattack quest, then make you way to the coliseum.
Once inside you’ll have to take on an advanced Cutter mech, but it isn’t all that hard to take out. Make sure you have lightning materia equipped (and link it to an elemental materia to infuse your strikes with Thunder), and don’t attack the arms unless the cutter is staggered. Just pop in and out of range between combos, and block whenever it charges you. Blast it with Thunder, and it’ll go down in no time.
Once you finish the machine off you’ll be confronted by Madame M at the entrance to the arena, and she will reward you with the Arcane Scepter. This staff is all about increasing Aerith’s MP, but it has less Magic Attack than the Silver Staff. It comes with two linked pairs of materia slots for a total of four, however, making this an ideal weapon for a support build.
The Arcane Scepter comes with the Fleeting Familiar ability in Final Fantasy VII Remake, which summons a fairy that will periodically attack enemies as well as after you use an ability or spell. It’s a magic turret, and a damn handy one at that. The proficiency bonus is earned after using an ability or spell once during Fleeting Famliar’s activation (so, while the fairy is floating around), so you don’t necessarily need to bank to ATB bars to pull it off (but, that will help).