It takes more than one I do believe but elementally appropriate attacks do more.  So water will nearly break fire.  But any attack will do some kind of damage.  

Okay, so when I pick my attacks during a chain, do I need to be setting up elemental combo sequences, or just worrying about doing as much elemental damage opposite to the orbs as possible?

Focus on doing damage to the orbs imo.  For every orb destroyed, you get another turn in the chain, so long as all 3 members have charged specials remaining.  Plus breaking orbs ups the damage.  The longer the chain is kept going, the greater the damage each attack does.  That's why the orbs are important, to setup lengthy chains.

Okay, fuck this game for fucking lying about levels.

I am level 39. A level 35 guy should not be able to stand a chance against me. This is bullshit. 

Wait what?  Did you mistype that?

Yeah meant to say 39, I'm several levels higher. I'm just getting really sick of the game lying to me about an enemy's strength.

Like, if I'm 39 and he's as strong as me or stronger, just tell me he's 39 or 40. Just don't lie to me and say he's much weaker than me when that's clearly not the case.

I'm level 81 and just beat a level 95 Monster with little effort. Are your gems, blades and chips good? How about your skill trees?  Have you leveled up your blades arts in the menu? Lastly, you want Attacker, Healer and Tank.  Some enemies even at lower levels have high attacks and a strong defense. Esp if it's a unique.

He's not weaker only less hp. It also depends what his weaknis is and what type of skills and blade you use + if you have any healers.

For example iam lvl 59 and killed a lvl 83 monster, took a long ass time but i did it.

Some bosses require you to do chain attacks otherwise you will just get wiped out. Chain attacks also can help affinity to unlock skills on some blades.

Okej soo, lvl 59 to lvl 64.
83 hours played( switch says 70+ though really weird)

Chapter 6 now
And have to say holy demm this game is amazing! Best jrpg i played in many,many years.

Its on its way to beating zelds tbh.