GMS:CrimsonWood keep 2,Magatia coming soon

Nothing has to fit an archetype.

Consider something with avoidable, mid-ranged attacks that deal 7-8k damage, and touch damage around that much. Enough to kill all but the highest level washed ranged chars, but not by any means certain death. Make it reasonably slow-moving and add warps to prevent cornering, and you've got a fairly challenging, but all means possible, battle for the ranged. As for the melee, there are numerous things you could do. Knowing Nexon America's love of invincible frames...

That would make it not a challenging battle, but a tedious, annoying, and money wasting battle.
*attack*
*invincible frame*
*boss moves*
*take damage*
*pot and move*
*attack more*
*invincible*
*boss moves*
*take damage*
*pot and move*

And a boss with those kind of invincible frames would only be use for 1 person, considering if you have like 12 attackers, only one will get their hit in while the others waste MP and take damage.