at Mythril Anvil AdamantiteBar It can be crafted at Mythril Anvil.
Forbidden Mask sits in the Expert-mode only tier of Terraria progression based on its rarity rating (5).
Menacing is the strongest prefix for Forbidden Mask — +4% damage — best offensive accessory prefix.
Forbidden Mask deals 16 base damage, 15-tick use time, 7% crit chance. Use the DPS calculator to see expected damage per second with prefixes and crit applied.