In Suikoden 2, is it possible to get the Hero from the first Suikoden to join the party? If yes, how and when can we do it?
There is a guide on GameFAQs. There seem to be some heavy spoilers, so just a small snippet
It's true that you can use everyone's lovable Suikoden 1 hero in Suikoden 2. And, if you play your cards right, you can even see Gremio as well. You must have Suikoden 1 to even attempt this.
There are some things you need to take care of first in Suikoden 1 however. The thing that is definitely required is your saved game must be at the last save point in Gregminster before you battle the Golden Hydra.