Blood Barrier gives a shield effect for the frenzy duration

src/server/config/effects/effectShield.js

@@ -0,0 +1,20 @@
+module.exports = {
+	type: 'shield',
+
+	amount: 0,
+	maxAmount: 0,
+
+	events: {
+		beforeTakeDamage: function (damage, source) {
+			if (this.amount > 0) {
+				let mitigatedAmount = Math.min(damage.amount, this.amount);
+				
+				damage.amount -= mitigatedAmount;
+				this.amount -= mitigatedAmount;
+			}
+
+			if (this.amount <= 0)
+				this.destroyed = true;
+		}
+	}
+};

src/server/mods/class-necromancer/spells/spellBloodBarrier.js

@@ -39,8 +39,14 @@ module.exports = {
 		obj.stats.takeDamage(damage, 0, obj);
 
 		amount = amount * this.shieldMultiplier;
-		const heal = { amount };
-		target.stats.getHp(heal, obj);
+		target.effects.addEffect({
+			type: 'shield',
+			ttl: this.frenzyDuration,
+			new: true,
+			noMsg: true,
+			amount: amount,
+			maxAmount: amount
+		});
 
 		//Only reset the first spell's cooldown if it's an auto attack and not a spell
 		const firstSpell = target.spellbook.spells[0];