Have any character get to Rank 50 on Barrier Magic to get Field Barrier 3. Then, have that same character get to rank 8 on Black Magic to get Regenerate MP. When you walk around killing enemies for SP without fighting, you will regenerate the lost MP and never run out, effectively giving you an unlimited SP gain. A good area to do this trick is in the flying fortress just after Zola leaves the team and goes through the other warp. In the room just before you meet Szabo are three lasers. When set off, a flying Mecha Robo appears for each one. Each monster results in a 2 SP gain. Just run from the save point through the lasers and back to the save point. Continue running this path and saving in between when the lasers stop dropping monsters. When you reach the primitive cube, before you enter the ruins, outside you will find butterfly monsters. Activate Field Barrier 3. Place your character in the center of the field, and tape the Left Analog-stick Up and Right Analog-stick Right. If done correctly, you will run around killing endless spawns of these monsters for +2 SP each. This is best done with MP Regeneration. You can reach level 99 in a Shadow in less than an hour. Check regularly in case of skill obtaining, and also if the butterflies get in a perfect chasing distance. If they do this, activate the barrier again and continue. This trick is also best done with Eyepatch or Black Belt.