Artmage Fiendsmith (60-card)

This deck has a simple, straightforward gameplay loop: summon medius, make Diactorus, and then profit.

This deck also features the card Theorealize  to better leverage the Fiendsmith engine. By sending Medius the Pure  to the grave, you can summon him out, summon the Artmage Power Patron , and make Artmage Diactorus  before changing Diactorus into a Light Fiend with the graveyard effect of Theorealize. From there it's simply:

Make Fiendsmith's Requiem > Requiem Summon Lacrima the Crimson Tears  > Lacrima foolish Fiendsmith Engraver  > Requiem effect equip to Lacrima > make Necroquip Princess  > summon Engraver > make D/D/D Wave High King Caesar .

The Artmage combo is well-defined and shown in plenty of videos and guides, so I won't cover it myself, but some important notes I like to make include:

• When completing the Artmage line, you often progress through Graflare > Litera > and Artmage Finmel . If you have gone uninterrupted, I like to make Cross-Sheep  with Graflare and Litera pointing to Diactorus before summoning Finmel. This allows you to summon Finmel to the zone and reborn the Litera, which means on your opponent's turn you can use Litera effect to summon either the patron or the Artmage Graflare , depending on which you need. This is best applied when you are able to set Artmage Masterwork -Succession- to further leverage the Cross-sheep to increase your advantage even further.
• It is important to note that the graveyard effect of Artmage Pact -Awakening- works well when you are able to use it with Artmage Litera . Litera's effect uses the "then" clause, meaning if you go chain link 1 Litera, chain link 2 -Awakening-, you get to summon off of Litera and the pop off of Awakening while only bouncing one monster to hand.
• Don't forget your extra normal summon from Artmage Academic Arcane Arts Acropolis for Medius the Pure as that can help you, especially when playing into boards. 
• There are a few substitutions that you can make in the extra deck, and I'd like to list a few of the cards worth consideration below:
  • a Moon of the Closed Heaven is still legal in Master Duel, so that is a worthwhile inclusion. However, because of the lock applied by the fieldspell, you are unlikely to make it mid-combo or to pivot to it at the end of your combo. For now, I am playing Cross-Sheep over Moon for this reason.
  • You are able to make rank 4 monsters using Medius and Lacrima, or by using two copies of Medius. For this reason, you can consider playing Gallant Granite or King of the Feral Imps to search Nibiru, the Primal Being or Ame no Habakiri no Mitsurugi if you decide to include those cards in your builds.

This deck's major weaknesses are Droll & Lock Bird and Nibiru, the Primal Being (if you do not see Fiendsmith cards). Ash Blossom & Joyous Spring on your Medius the Pure can also stop your turn if you do not see an extender. For these reasons, it is always best to lead the Fiendsmith engine to draw out as many handtraps as possible before attempting to resolve Medius.

IN CONCLUSION, I love this deck! I am very happy to see it coming to Master Duel (finally) and hope you have fun playing it as well. This is just one build of the deck, and it has many other engines and sub-engines that can assist with its gameplan. Don't shy away from experimentation!