Focus on the necromancer.

The skeletons will all die if the necromancer dies, you know that. And he should still have very little health left. However your only offensive spell deals tiny amounts of damage, and your Hex has probably worn off by now. You could cast it again, but would even that be enough?

Then you realize... You don't just have a spell for increasing damage taken, but also damage dealt. You've never tried to use your buffs on yourself, since you don't have any damage output to be buffed and your minimal health doesn't make a Ward worth the mana cost. But now if ever is the time to try.

You cast another Hex on the necromancer, to which he hardly reacts, and then you prepare an Empower spell and try to target yourself. And indeed, you feel the spell's effect envelop you as you feel stronger.

Now your attacks will deal 80% more damage than usual to him, so you cast Sinister Grip on him and keep it up, your arms reach up and your fingers spread out magically as a red and purple swirling glow envelops your boss. This finally pisses him off to the point that he stops ignoring you, turning away from his work and walking towards you.

"What is taking you idiots so long!?" he scolds his skeleton minions, causing them to halt to listen to their master when they were literally one second away from grabbing you. You keep the spell up, knowing that you have no other way out. Panic is starting to consume you, but you stay focused.

The necromancer slams his staff into the ground, and you feel the sting of some negative status effect. You feel your body stiffen, making it harder to keep casting or even stand up. Only your short, wide stature keeps you from falling over. The skeletons, no longer distracted by their master, return to attempting to grab you.

You struggle against the spell effect. Continuing to hold your arms up feels like moving limbs while they're asleep. You have no feeling left in your body and it's as if some magnetic **** is pushing against your every attempt to move even slightly. You feel several skeleton hands against your robe, fingers curling to grip you-

...And then they roll off of you as the skeletons fall apart and the necromancer burst into smoke, the last thing you see being his facial expression which essentially communicates "ARE YOU FUCKING KIDDING ME?!"

*Ding!*

You breathe a sigh of relief deeper than you thought your lungs could fathom as you stare forward in disbelief. You did it. You actually killed your own boss. And given the amount of XP you've been getting for assisted kills, you wonder how much you just got for actually killing him yourself. You're a bit anxious about checking your stats here in the boss room, but eagerness wins against caution and you open your stat menu. The first thing you notice is the unusual label "Premature Rigor Mortis" in your list of active status effects, bringing your attention back to the fact that you still can't move. Now you know at least that it was a paralyzation spell you got hit by, if that wasn't obvious already. It only has a few seconds left, and as soon as it disappears you can feel your body go slack again, and ironically only then do you fall forward, not used to the lack of rigidity. You stand back up and focus on what's really important, namely your stats.

Dark Caster
Lvl: 13
Melee Attack: 0
Ranged Attack: 0
Armor: 0
Weakness: Melee
Special Abilities:
Hex: Reduces target's damage resistance by -50% for 40 seconds.
Curse: Reduces target's attack damage by -50% for 40 seconds.
Ward: Increases target's damage resistance by +50% for 40 seconds.
Empower: Increases target's attack damage by +50% for 40 seconds.
Corrode: Damages target's armor and weapon by 60 durability.
Shadow Trick: Blinds target for 10 seconds.
Sinister Grip: Deals 5 HP/sec to target instantly.

Ability Gained!
Blood Ritual: You gain MP equal to 25% of the target's HP lost for 20 seconds.

Ability Gained!
Dark Influence (Passive): Monsters of level 12 or lower are more inclined to obey your orders due to your arcane wisdom.

Wow... You gained four levels from that kill. You're disappointed to see that you got no new offensive spell, however this Dark Influence ability seems very interesting... You wonder what extent of control "more inclined to obey your orders" mean. Does it mean that you can essentially brainwash other monsters, or just make them not laugh at you as hard when you ask them to do something? You're eager to explore the possibilities, especially considering that you're the highest level monster in the dungeon except for most like your boss and The Keeper...

You look around the room, thinking you should probably check if the door will open now, but on the other hand you have the opportunity to explore it for a bit before the boss respawns...