Final Fantasy I-III – I’m not sure these games even had summons. I think III might have, but I don’t believe I and II did. Correct me if I’m wrong.
Final Fantasy IV – The summons were definitely a part of the plot in this game. You had the whole thing with the one character (I just can’t remember names right now) gaining powers as a summoner and there was other stuff. It’s been a while since I’ve played this one and I’m a bit sketchy.
– Final Fantasy VI – The espers were a major part of the story. Terra is half-human and half-esper. Everything related to magic is connected to the espers and at the end of the game, the espers disappear.
– Final Fantasy VII – This one is an oddity. There’s a variety of summons available, but it’s not really connected to the plot. Instead, it’s more just a part of magic/materia, which is connected to the whole "spirit energy" part of the game.
– Final Fantasy VIII – This is a big one. You have the GFs, who lend their power to raise your characters’ strength. And then there’s the whole thing when your characters realize that the GFs could be causing their memory loss. Yet, in the end, they continue to rely on the power of the GF.
– Final Fantasy IX – I haven’t played this one. Maybe someone else can fill it in.
– Final Fantasy X – The aeons. Summoners pray to the faith to save the Aeon. The Final Aeon will defeat Sin. (Not!) At the end of the game, the Fayth finally stops dreaming and the aeons disappear. (This is eerily similar to what happened in Final Fantasy VI.)
*Might be minor spoilors*
FF1-3 ignore these idont even think they have summons
FFIV- Summons were really useful in battle but not really to plot. There is a caller called Rydia who can summon for massive dmg but thats as far as it goes. You also fight some of them like Leviathan and Bahamut to gain them.
FFV- Im not too sure, I know you fight some of them because I remember fighting Siren but Im not sure if they important to battle or story.
FFVI- Definitely important to story and yes they give you abilities but as far as summoning they dont do very much dmg.
FFVII- Agent explained
FFVIII- Agent explained
*Major spoilors below*
FFXI- Ok storywise summons are probably one of the most importnt thing in the game. You have a princess who can summon and the mother trying to steal her power. Then you have Bahamut kill a whole bunch of people and Alexandar and Bahamut fight. You find out the princess came from a grp of summoners. Summons are like a whole stroy in theselves this game but i never used them in battle.
FFX- Agent explained
FFXI- All I can say is there gonna have a summoner class 🙂