Summon Circles (also known as Pentagrams), are red circular symbols found in a dungeon room near a boss. To activate one, Zael must be standing on it and activate Gathering. The pentagram should "summon" multiple enemies.
Summon Circles are usually used to gain experience. The enemies you kill and also give loot, so it is an easy way to farm status boosters. The downside is that each time they're summoned, the enemies will give less EXP. Zael can also deactivate and reactivate Gathering on it to summon more batches of enemies.
Blue Summon CircleEdit
Blue Summon Circles are available from Chapter 36 until Chapter 40. Horace gives you a summon stone that he found whilst running away from the Gurak. Blue Summon Circles work like its counterpart. Zael must activate it using Gathering and instead of summoning enemies, you summon Horace instead. These blue pentagrams are used usually when there is a time of crisis or when you need to sell/upgrade equipment. Blue Summon Circles also appear in a dungeon room near a boss (except for the final boss). A Summon Stone is required to activate Blue Summon Circles.