Commander's Brew Episode 257 - 5-Colour Secret Karrthus
Five-colour secret Karrthus is a wild idea for a Commander deck and it's not for the faint of heart. If you want the full lowdown on this deck I really suggest you listen to this week's episode because there's a LOT to set up with this deck, but if you can make it happen I think you'll be very pleased.
The basic moves of the deck involve getting your mana settled (Golos helps with that) then tutoring for a few cards if you don't already have them in your hand and then just getting it done! Cast Conspiracy naming Dragons, then donate it away, and then it's as simple as casting Karrthus which you obviously already tutored for. Also, feel free to blink Karrthus or reanimate it or mess with the creature type it names with something like Artificial Evolution. The possibilities are many, just make sure you keep a starting hand with a tutor or Karrthus himself in it! It'll be fine!
5-Colour Secret Karrthus