Castle Crashers Remastered

I did it with an actual player online. You may need to be on an actual xbox live profile and not a guest? I want to believe it will work and maybe being on the guest is what's causing a problem? I'm not sure what else to suggest :/

got it to work. it has to be two new players that you haven't used before or else it skips one area that you need.

for it to work you need to start at the very beginning where they are dancing.

When I got the achievement, we both were using existing characters. I was on a high level Red Knight and my friend was on a level 16ish Blue Knight. I started a game and selected the Home Castle level from the map. My friend killed everything. After the Castle Keep level, we were put back on the map and I selected the Barbarian War level. Upon my friend killing the Barbarian Boss, the achievement popped for me. Then we started a new game and I repeated the process for him.

well that is cool. just for me, it wouldn't pop until i chose two new characters.

I did it the first time like how you did but it never unlocked. don't know why it required two new characters for me but unlocked for you with high level ones.

ah well, got the achievement.

Just a note for anyone doing this: dont let your 1st controller have an animal that does damage. if it attacks then it will void it

Having an animal does not void it. I just got it with the bat

I can confirm that this achievement is obtainable using a guest profile.

Can confirm that if you have an animal that attacks it will void the achievement. Best to unequip any animal.

I just got the achievement after multiple tries, and the only difference was in the final run my main character didn’t pick up a weapon. In the previous runs it had, but never attacked. Hope this helps someone.

Got the achievement with two new characters rather than one new and my leveled up character but got the chevo right after beating the final boss!
It’s okay to have the main account die and revived as well

I did it with my other account, while my account was idle and the achievement didn't pop. Help lol

So let's see if I'm understanding these comments correctly:
It seems guest profiles work, but maybe not. It seems you can have an animal help, but maybe not. It also seems that you need to start with 2 new characters, but maybe not.
Got it, thanks!

I attempted this three times before I got it.
Scenario 1) Original character and I had attacking pet
Scenario 2) New Character for both players (also died once against the boss)
Scenario 3) Original Character with non attacking pet BUT I did two things differently that I know I did not do in either of the above two scenarios. I am leaning towards the first one being the reason, but the second is listed just in case. Firstly, I always selected Barbarian War with my second controller in the first two attempts. I don't know if not choosing the level both times with my main character is the reason, but it may seem like it (Home Castle and then Barbarian War when it forces you to the map from Castle Keep). Secondly, I didn't move the joy stick to get out of the ground. I made sure to do this, as well to try to do things as safely as possible. I would just make sure to select the levels with your primary character just in case that matters. Otherwise, I suppose it's possible it's just buggy.