Epic Cards Battle

Scepter says that it only reduces damage from attacks. However, when it is hit by vengeance, which is a trigger and not a creature, it will reduce the damage to 150.

This is correct I think attack refers to unit attack. Spells are usually referred to as damage. I like to use the specter as a defense vs wrath of bahumat because his ability protects him from spells as well which is kinda cool.

It reduce Special type of attack, not only by Creature cards. So it performs correctly.
Perhaps it's the word "attack" causes confusion. We will change it to damage in future update.