The Blue Talisman can be found in the north of MAP12: The Temple of the Oracle (Strife) in the first worshiping hall. This becomes unlocked after speaking with the Oracle.
This quest item was added in the 2014 The Original Strife: Veteran Edition. Collecting all 3 (Blue Talisman, Green Talisman , Red Talisman) grants a permanent super strength power-up and the Berserk Reborn Achievement.