Machine and May start with Ancient Gear Reactor Dragon, a Level 9 Earth Machine-type monster with 3000 Atk and 3000 Def. The latest boss monster has appropriate boss stats. However, it does require 2 cards to hit the field effectively. The structure deck does provide those 2 cards, but even without them, Ancient Gear Reactor Dragon attacks with impunity by blocking all effects of cards that activate until the end of the Damage Step. And then at the end of that Damage Step, if it attacked, you get to destroy any Spell or Trap on the field. For a monster that can be Normal or Special Summoned, this boss has decent protection and not a lot of draw backs. If it is Tribute Summoned with the correct cards on the field, its attacks become even more devastating. 
 
Geartown with Ancient Gear Gadget makes Ancient Gear Reactor Dragon truly shine. An Ancient Gear tributed for Ancient Gear Reactor Dragon gives it piercing while a Gadget tributed for it gives it 2 attacks per battle phase. Geartown allows it to be summoned with one tribute, and if it's Ancient Gear Gadget, it will gain both effects. That can be a very powerful battle phase. Combined with the regular effects, Ancient Gear Reactor Dragon becomes a do or die monster. Clear back row cards and inflict piercing damage while not worrying about any effects from anywhere can win the game. It may not be splashable in other decks, but Ancient Gear Reactor Dragon is a worthy boss monster for the archetype. 
 
Score: 4/5
Art: 4/5
 
-WarlockBlitz

Ancient Gear Reactor Dragon
 
Starting off Ancient Gear week is the theme's boss monster from their latest structure deck, Ancient Gear Reactor Dragon, and it certainly lives up to its name. Sporting 3000 attack and defence, AGRD is a level 9 earth machine. All of which are reasonably well supported. AGRD also comes with 4 effects, 2 of them gained when it's tribute summoned.
 
First off, when he's tribute summoned by using an Ancient Gear monster, it gains piercing. When it's tribute summoned using a Gadget monster, it can attack twice every turn. Both good effects, even if tribute summoning doesn't happen much outside of monarchs anymore and tributing Ancient Gear Gadget will fulfil both conditions off of just a single monster.
 
For AGRD's 3rd effect, it gets an upgraded version of the standard Ancient Gear effect when it attacks. AGRD prevents the opponent from using ANY effects when it attacks until the end of the damage step rather than just stopping spells and traps. And finally, at the end of the damage step when AGRD attacked, it can destroy one spell or trap on the field.
 
A huge improvement over Ancient Gear Gadjiltron Dragon and a huge boon for the deck as a whole, Reactor Dragon is a powerhouse of a monster with equally brutal effects. And still a force to be reckoned with even if it's summoned without tributing for it.
 
Advanced 4/5