Stop Encounters
Head to the nearest cave or dungeon and remove the game from its slot in your PSP. The random encounters with characters that often appear in the game will stop completely. Make sure to put the game back in when you come to fight one of the bosses.
Fight Secret Character
Go to the arena in Tatori at any time during the Emblem quest. Take part in four battles for the secret and powerful character T'Nique to appear. Answer "Yes" when he challenges you to a fight.
Acquire Ashlay
Make your way to the arena's audience stands and Ashlay will be standing as long as Cyuss isn't in your party. Speak to Ashlay and after a quick chat he will leave. Win a round in the arena using Roddick, and then walk to the Tatroi docks. Ashlay will be waiting there and will join your group.
Get Erys
If you have Mavelle, Ashlay and Ioshua, go to the Old Race Ruins near Silvalant. Walk far into the ruins until you encounter Erys in a room. Ioshua will get mad at one point; select the second on-screen option when he does. Erys can now be recruited.
Unlock Pericci
Begin a Private Action in Kratus when the Emblem Quest starts. Go over to speak to Millie and at some point she will ask you something to which you can answer with one of three names. Select "Pericci." Go next to the cat with Roddick and play the ocarina to recruit Pericci.
Obtain Welch
Go to Ionis if you have the Silvant Emblem and seven or less members in your party. Walk to the location with two bridges and head to the forest between the bridges. Keep going until you see a house and you will be given some options; pick the first one and Welch is yours.