Valkyrie Profile: Lenneth - Character Art

Unlock Seraphic Gate:
Beat the game and save after the Fin screen. You will now be able to access Seraphic Gate through the main menu.

Secret Scene:
Wait after the credits finish and you will see a scene involving Bramms and Lezard. This can only be posible if you get the A ending.

Unlock items by beating the Seraphic Gate multiple times:
Each time you defeat Iseria Queen in the Seraphic Gate, you receive a chest and 1,500,000 exp for your exp orb. Once you defeat her 10 times and receive the Angel Slayer, all successive playthroughs will result in anther Angel Slayer and the orb exp.

Tri-Emblem:
Beat the Seraphic Gate once.
Book of Riddles 1-8: Beat the Seraphic Gate 9 times one book each time.
Angel Slayer: Beat the Seraphic Gate 10 times.