the more powerful summons are as listed:
Ring of light- Wraith, good spell caster uses energy spells
Ring of fire-Blood elemental, physical attacker, when he gets hit it casts a weak form of vitalize on everyone in your party.
Ring of Stone-Blade of Urath, Physical attacker VERY STRONG, bad defense.
Ring of Darkness-Spirit of Larahah, must collect 8 torn out pages of the tome you get from killing Sonrehan, I never did it so I dont have any info.
THE 4 DRAGON RINGS: water, 4 winds, forest, jade.
These are the first summons on the 4 dragon rings that can be found in Orenia after you find the first 4 in Medeva.
Water- Blue imp- Spell caster, can heal and cat Ice spells.
4 Winds- Celestial Samurai- Physical attacker pretty strong (my favorite help)
Forest- Poison elemental- Physical attacker causes poison staus on enemies, not that great of a summon if you ask me.
Jade- Jade Golem- Slow as a rock, but a very powerful physical attacker, good for bosses that don't move around much. his attack is blunt damage which is the only thing that hurts some stone enemies, also has spell Jade beam that causes good amounts of damage.