99.97% insta-kill mage assassin (5e Optimized Character Build)
From D&D Wiki
Note: this build isn’t for practical use, it’s for stupid fun that works. It’s overpowered in a specific niche of gameplay, though can be impractical in more common situations.
The main idea of this build is to use the shape change spell to turn into an intellect devourer, an intellect devourer can use its action to make an intelligence contest against an Incapacitated creature, and on a success, eating it’s brain, and taking control of its body, instantly killing the target.
For race we are going to be a hobgoblin for their saving face ability giving up to a +5 bonus to our roll.
3 levels lore bard so that we can lower the amount the enemy rolls by our inspiration die (1d6) and because it’s a generic intelligence contest without an associated proficiency, the jack of all trades feature also applies since we don’t have proficiency in it.
17 levels divination wizard gives us 3 dice we can roll right after our rest, these dice give use preset rolls we can use for our check.
After this we have a +16.5 and our choice of several rolls or to roll normally. Assuming we target a creature with a very high intelligence of +10, our chance of success is about 92%.