Ok, I've known about characters being compatable with gfs since like the start of ff8 but I don't understand a good way to raise it. I have Ededn with only 350 with every character and I dunno what item increases this or if theres a faster way to get the summon more compatible. Same thing with Bahamut and every other GF except things like ifrit quezecotl shiva siren and brothers who thouigh i have used nearly no items, the all have 1000 compatibility with the person they've been with most of the game.