i got his horn in chapter2 in the brige distinct. it can be used to summon a beserk of level5 once per day.
then i hear if i have a diamond, i can upgrade this horn to summon level7 beserk.
i don't know how to upgrade this, please help me!

I do not want to go so far as to say that what you have mentioned is not true, only that I can find no mention of it in the cheat book.

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The silver horn can be upgraded with a diamond, and it can be upgraded again with a bejuril (5th level to 7th level to 9th level on the upgrades). Go to the weaponsmith on the platform south of the Adventurers Mart and be sure you have some cash on hand.

Very interesting...thanks...I stand corrected...my "marvelous book" therefore does not tell of all the wonders of the game like I had first imagined.

you mean i'm saving that stupid gem n thats all it does? SHEESH

There is actually one other use for the bejuril that I know of. You can find one on that same map, though, so you don't need to save one for that.

Wonderful, I sold my diamonds, and bejuril stones, not realizing they had any other use, and the buy back price on these is not user friendly,