Diablo 4 is filled with demons, spawns of Hell, and endless waves of monsters that players get to slay with satisfying, righteous indignation. Aside from the minions of Hell, Diablo 4 features a good number of epic boss fights too. Some of them can be found in the game with things like World Bosses and events, while others are classically spurred on by progressing the main mission.
Vhenard and "The Cost of Knowledge" quest present one of the first challenging bosses that mission progression throws at the players. This boss fight might pose the first real test of the game's difficulty as players will have to duck, dodge, and damage numerous enemies that spawn during the fight.
Updated by Chad Thesen on July 3, 2023: This guide previously did not cover what rewards players can be expected to get from the fight. Some players have shown confusion after receiving the bare minimum rewards. A section has been added at the end to help players be aware of what they can expect to receive as rewards after they have defeated this enemy in the game.
Avoiding Damage
Stay out of the bad! The Vhenard boss fight at the end of "The Cost of Knowledge" quest will have players scrambling to stay out of the constant area-of-effect attacks from enemies while still trying to do some damage. Technically, there are three different types of enemy area attacks that players should be avoiding at all times throughout the fight: Hell Spawns', Vhenard's and the blood stream that connects Vhenard to her Hell Spawns. Coincidentally, all three types of attacks are also the color red. Also, each phase of the Vhenard fight will spawn increasingly more enemies.
Each new round will spawn more enemies than the past one, so the fight gets increasingly more difficult as time goes by. In each phase, Vhenard will summon Hell Spawns, which are medium-sized baddies. Hell Spawns shoot the electric-looking smaller flying red balls, Vhenard's attacks are red snaky, floating things and there is also a red blood tether between Vhenard and the Hell Spawns that will damage players when touched by it. Do your best to avoid all three of these attacks in the fight. Also make sure to stay off the stairs on the sides, as The Black Lake will instantly drain a character's health.
How To Beat Vhenard
Winning the Vhenard fight is going to be mainly based around two things: movement and ranged damage. During the fight, you cannot damage Vhenard directly and must focus on the multiple Hell Spawns that are tethered to Vhenard through various waves of enemy attacks. Due to the fact that Vhenard's Hell Spawns are constantly in rapid movement, players will need to rely on their ranged abilities most of all. That means that melee classes are going to have the toughest time with this boss fight. So, Barbarians and Druids are probably going to struggle with this one.
It is recommended to respec your class for ranged damage, mobility or survivability if you can't win the fight in a current build. The combined act of avoiding all the insanity on the screen while laying out damage to the rapidly moving Hell Spawns can test a gamers skills and patience. This gets increasingly chaotic as the amount of enemies increases and the type gets more deadly. Eventually, Vhenard will begin to spawn Spewers, which fire ranged puss at you, and gigantic Pit Lords who have horns and swords the size of buildings. Make sure your fingers are warmed up for this boss.
What Rewards Do You Get?
After defeating this enemy, you will receive some experience and some gold that will scale depending on the difficulty the game is set to. You will also receive a rare dagger called Mother's Knife that will not be as good in the hands of some classes compared to others. The Cost of Knowledge quest will also be completed upon defeating Vhenard.