In order to find the Summon Spirit Maxwell, you must first find the Derris Emblem in Derris-Kharlan (which is late in the game, near the end ). Then, go to Exire (Half-elves village ) and go to the house with a man inside. He is the person that says that a team of half-elves and humans is a rare combination. Go up the stairs in front of his house and walk around to get to the back, which leads to secret passage. Walk until you see a tombstone. Equip the Ring of Fire, Water, Earth, Wind (which are Ruby, Aquamarine, Opal, Garnet). Then, you will fight Maxwell. He has 60,000 HP (easy mode in the customize menu) or 90,000 HP (hard mode). He also knows strong level 3 magic spells such as Thunder Arrow, Raging Mist, and Meteor Swarm.