Event shop tiers have existed for a few years. Not all event shops have tiers; the Goblin Market shop didn't, for example, and the upcoming RISE shop, to my knowledge, did not have tiers in KMS.
Also, events with tiers give a stat-boosting skill which increases with each tier, and grant a prize box upon advancing each tier.
Flames are actually rather common, you should look into building your monster collection and crafting.
Hard Hilla's cage and Lucid's bombs (along with, for that matter, Chaos Crimson Queen's breath, Ursus' bombs, and Papulatus' bombs) are designed to work with multiple party members. Hilla's cage can be attacked from the outside, and the bombs (and breath) deal less damage when you concentrate multiple players in the same area.
You either have to bring along friends who can help you with these mechanics, kill the bosses fast enough solo, or utilize invincibility frames to avoid these attacks. Heroes Will can—to my knowledge—still grant you immunity to Hilla's cage if you time it carefully, Queen's breath can be nullified or reduced with certain skills, Papulatus bombs are survivable, and Lucid/Ursus I'm unsure if they can be nullified as I've never tried, but they should be blocked by certain i-frame skills or long-duration invincibility skills (such as Full Metal Barrage, Omega Blaster, and maybe Hunter's Prey?)
No class can use their class-specific skills if they equip a weapon not for their class. If your character cannot attack at all, they may be a class that has a skill bound to the normal attack function, such as Aran or Demon Slayer.
However, since a beginner's sword doesn't let you use any skills, it's not really worthwhile to use a beginner's sword in place of anything.
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