Before meeting the Grand Sage, I used this team:Tigertan Guard and few normal skills Titoro Fire and passive skills on other skill trees Quickapent Grass and few normal skills Eaglin Electric and few flying skills Armordilla Mainly Guard skills However with thise minions I have not been able to defeat The Grand Sage but only few standards battles were tricky.
My team is a Titoro with really high speed gems, a sumole with a full torment skill,a falcona or an cerebus I switch them, a meglatron with precision missles and a elislime. But i still can't beat level 6-1 with the student who says let's like uh be best friends!!!!!!!!
Lightina is the best of all, fastest speed, one of the highest power, only HP is low and i know she can be knock out easy but if you give her 3 Attack gems and 1 HP gem and choose the Electric skill tree, your Lightina gonna be the strongest rival of your enemies(you don't need Speed gem if you level up the Agility on Support skill tree)!!!
Suggested skills: Spark lvl 4, Electrocution, Thunderstorm lvl 3 and Overload lvl 2.
My team is:
Domisteam.
Lightina.
Dracolt.
Seiryu.
Sobek.