You don’t just have to place offensive spells into the ring, or even spells that affect others. You can cast spells such as blur, enlarge person, and spirit guardians into the ring, and then give those defensive buffs to your frontline fighter. This is twofold, first, you don’t need to spend a spell slot and a turn casting the spell and affecting your frontline, and second, your fighter can run up, draw his sword, and spend an action casting the spell. Then he’s got a defensive buff right in time for the enemies to attack him. Any spell can be placed into the ring, offensive or defensive, as long as it follows two rules: It must be level 5 or below, and the total number of spell levels inside the ring must not exceed five. Otherwise, go nuts with it!