Do the enemies and some items change between classes?

[★Kawasaky]

Because until now I only got a 3 headed dragon as first enemy, but now that I have more unlocked, when I use others I don't see that dragon anymore, but a pendulum monster, or weapons that didn't appear on chests before like a stick with bombs, or the first time I used the pirate, after 15 hours I saw boxes and chandeliers with legs as enemies.

[boovie]

No, everything what happens in the game is just based on a random number generator. It is possible to encouter any enemy or any item on the first play. So you just had a bad (or good) luck. Weapons are split into tiers so more powerful weapons won't drop at the begining of the game.

The boxes and chandeliers are not standard enemies, these are spawned by the "animate" curse so you need to obtain the curse first before these enemies start showing up.