One of the most (apparently) incomprehensible challenges is explained here.
In Dragon Ball Legends we are asked to battle with a Super Warrior. But, surprise, it is not a Super Saiyan what we need. Super Warrior it’s the tag’s name of (mostly) EARTHLING characters. Thus, you will need to battle with one of these in your “active” team (i.e., the one that actually battles, not the roaster). Here it is the list of the Super Warriors.
Now you are ready to complete this type of challenge with success, but not forget to share the Healing Muffin with your earthling friends!