The only cheat code I could find for the game, and it might help you I really don't know, but some maybe able to really find this unlockable really helpful and I am glad I could help you.

DVD Easter Egg: On the companion DVD, from the Title Menu -- Select Data, Highlight Gallery, Press "Right," Then Enter/Confrim your Selection.

Go to the Chaos Gate at the third server and choose to write a new keyword. The first two words can be anything, and for the last word enter "sea of sand". You will always get a power up spring and the weather will always be sunny. Take a weapon and power up it until it cannot be more powerful. Note: It is recommended that you to take a high level keyword, like 42 and above, and that you have the Grunty Flute to avoid encounters with very powerful monsters.

The crimson raid and the fishkin are rare items in .hack 2 to get the crimson raid defeat anglomore. To get fishskin defeat a squidbod they are resistant to physical attacks so only use magic because one hit will destroy it it's better if you data drain two at once for better chances but yeah with fishkin you can summon merrows