It becomes popular to group up with your friends in Last Chaos.You just need to join the party in game.it will allow you to take advantage of different classes strength's and weaknesses.
There are three different party types in game:Equal Party,Precedence Party,and Combat Party.Each party has its own strength,weaknesses and goal.Party is the only place where you can see other players' level. you can get your party window by using 'G' or 'ALT-G' on your keyboard.
Level restrictions are not required for Equal Party and Precedence Party.Experiences,gold and drop items are divided equally between party members in Equal Party.Experiences are divided up according to damage made to the monster in Combat Party.Drop items belong to whoever picks them up in both Precedence Party and Combat Party.
When you start to form a Party,just click on the player who you want,then choose one of the three party types.players will get an information to confirm or cancel this party invitation.If you want to add more members to your party,repeating this action for others.The maximum number of party members you can have in a party is up to eight.you can double-click their name to remove them from the party,meanwhile you can double-click to quit your party.