Easy experience
Go to the catacombs in any level level 1 recommended Have all the characters who you want to gain experience for and a healer required When the battle starts attack your own teammates After the attack your character will gain experience The higher the characters level that you will attack the better You can either heal the damaged character for experience for the healer or kill him or her much more experience will be gained Note If your characters are killed their Luck status will be reduced
Echidna
To get Echidna in your party select the quotYoure about to find outquot option when facing her Win the battle that starts with an overkill defeated and not kneeling on ground When you face Echidna the second time make sure that Spreo has his final Samurai rank by getting his legendary weapon Once again defeat Echidna with an overkill
Jade
To get Jade in your party defeat him with an overkill the first time you face him and defeat all of his men Also win by an overkill in the second battle against him Then select the quotI wasnt really going to kill himquot option when it becomes available In Chapter 4 or 5 get the quest that involves guarding a gold transport Jade will be there and flee Go to the guild and look for a letter from Jade Fight him and he will join your party
Tia
To get Tia in your party do not let her die in any battle that she is in except for the first golem battle If she dies there she will appear in a different location Also read all of her letters After getting the twelfth letter she will appear in Silva or Aphen