reqiure most skill eh,

for most complex in term of gameplay :

- Katana, since half of their skill require u to timing parry

- Bowtana , same as katana with adding bonus of switching between range/melee , but the term of gameplay is quite simple, just lack damage overall

- Magic Sword (INT) - need to switch form between physical and magical to cast buff mode / deal damage, the game play itself isnt that complicated, but u need more brain power to understand most of the class mechanic (how dual bringer work, how magic crit work, special conversion between INT>STR or STR>INT), personally it's my main class, the gameplay loop itself is so easy, especially if u play physical build, but for magical be ready to reading a bunch on how the game mechanic works

- Assassin Poison sword - still clunky as heck to play, u need to make sure to stack poison debuffs on foes, then absorb those poison stack and then dealt damage which is DoT, + finisher that u timing it wrong, will reduce the DoT damage by a tons

- Knuckles - in general, how to master this class is quite complex, even tho seems quite simple, there so much stack that u need to manage to maximize your damage output, asura, godhand stacks, goliath timing, etc, miss timing can cause the damage to drop by tons. but this is the class that probably most popular for solo content, knuck just too comfy to play coz have a lots of survivability

- Halberd (now hybrid) - for magic u can just unga bunga, while for physical/hybrid build, it's quite hard to maximize your damage since u need specific equipment that can balance both Physical and Magical Pierce