EXTRA: Seal IIIG 5

First select Queen Sigma (you can use other characters but she is by far the best as she has max default stats) and load into a map you are confident on, turn on: Endless, Hurry and Arcanas then load into game.

Immediately choose the VIII - Mad Groove Arcana and pick up a couple of support items (Ideally a Crown). Then use your Re-rolls to focus on getting the Victory Sword to max level as fast as possible, then max out the couple of support items and pick up whichever Arcanas you prefer.

At this point just proceed to banish Weapons every time you level. You start with 118 banishes (as Queen Sigma) so make sure you finish with no more than 78 (I recommend leaving a cushion if you can).

Once you have banished all options; end the game and the achievement should pop.