It was a dark and spooky night in the forests of Barovia, perfect weather for an ambush. The mists swirled low, reducing visibility to maybe a hundred feet. The party was on edge, weapons out. It was always a gamble walking at night in this cursed land, but sometimes you just had to roll the dice.
As the group crested a small hill, their hearts skipped a beat. There, on the bottom of the rise was a group of ogres. Nasty creatures carrying leather clothing made of human skin, and wielding huge clubs.
Quicker than his companions, the elven archer fitted an arrow to his bow and let fly.
A perfect hit. Another arrow flew, also finding its target. The ogre went down in a heap, killed in the opening moments of combat.
"Wait, wait, wait... how did you do that much damage? You are only level one!", the DM yelled over to one the players.
A conversation ensued, with the player going over the various different rules he had cobbled together to form the ultimate min/max level one archer. While technically correct, the character was a role playing abomination that the entire party voted unanimously to exile from the realm of Barovia.
Now, in this case, the player who created that abomination was me, and I agreed to go along with the, uh, recommendation of the group because I'm not a jackass, and would rather have a good time with my friends than insist I'm right and keep playing my ridiculous character.
But what do you do when the player does not want to part with their character? Or when the player would simply create a new min/max abomination and continue their reign of terror?
This is when the DM gets creative, as there is far more to tabletop role playing games than just combat. Dig in to the character's weaknesses, so that the hulking min/max player is constantly losing out on loot, or falling into traps, or getting charmed/held/dominated.
Maybe, with some creative deviancy, you can convince everyone to make a well rounded character. Or... well...
The mind flayer advanced, grabbing hold of Thorn, and sucking the brains out of the witless former member of the group. Strangely, the rest of the party laughed as their former companion's lifeless body slumped down, brain dead after the ruthless attack.
After feasting, the mind flayer seemed content not to attack the rest of the party and just disappeared into the shadows, its job complete.
The DM looked at the remaining party, "I guess that is the end of Thorn... Normally I wouldn't send a mind flayer at a party of this level, but I thought it would be a fun way to kill Thorn, since <playerName> is no longer playing with us.