Here is a cheap and probably the most efficient way to get your Ability Master Gold Trophy... You will need 5 Baurg, 2* and max level. https://exviuswiki.com/Baurg You enter a battle and spam Chakra. It costs 8mp and gives you back 13 mp. It also restores 30% of your HP so doing this in Earth Shrine (or somewhere easy) you can repeat this indefinitely. If there are no Baurg friends, enter without a friend.