Alter Aeon Online Help

Keywords are:  'assist'

Format:
assist
assist <character name>

The 'assist' command allows you to assist your current group, or another
character, in a fight.  If you are in a group, you can use the assist
command to join into battle with the rest of your group.  You can also
assist someone directly, for example 'assist Dentin' to aid the player
'Dentin' in his battle.

You will begin fighting the same target as the other character after you
assist them.