So you wanna be an AOE blade? the first thing you need to do is rush to level 65 by doing legendary redmantis quest, reonan quest and darkon office quest. once you're level 65, max the blade dance skill because this will be your main skill till endgame.
The equipments you're going to need are:
Recorn/Rescorn set : this set is a good starter set as you go through your journey of becoming the best AOE blade as it has Max FP to sustain your blade dance FP needs, Max HP to increase your lures and def to reduce monster damage you take.
Guardian sword : this is the best weapon you'll ever need going to level 75 where you can either change to Historic sword/axe because of its Dex +5 to increase your blade dance damage and HP +10% for your survivability.
Dretra sword : you'll only want to equip this if you can't find a Guardian sword to use, it has higher base damage compared to Guardian sword but the stats and HP increase is much better than hitrate and attack speed as you have no need of both.
Einy/Akan Set : this is the absolute best set you'll ever gonna need till 120 and it's arguably better or same as Blain/Virain Set, it gives a huge Dex stats, Skill damage, and Max HP which will boost your blade dance damage.
Historic Sword : this is based on preference, this sword give Dex +7 and Critical Chance +10%, it does increase your blade dance damage but you'll trade survivability you get from Guardian Sword, if you have a high level RM that can sustain your survivability this is the weapon to go.
Historic Axe : This will be the best weapon you'll ever need going to level 90, this will greatly boost your survivability allowing you to lure much more monsters, it adds HP +15% so with both in hand it'll increase your HP by 30%
Sword/Axe of Iblis : this is a good weapon if you ever find your hands on one, it has 5% skill damage and Dex +5 that increases your blade dance damage, you can pair it with historic axe for survivability and increased damage.
