This is a deck meant to make use of the Devastating Onslaught to devastating effect, getting lots of value by copying things like Threefold Thunderhulk, Overlord of the Boilerbilges, Solemn Simulacrum or the dragon tokens from Dragonmaster Outcast.
With Zookeeper Mechan you can cast Solemn Simulacrum on turn 3 and copy it twice with Devastating Onslaught on turn 4, searching 2 lands and drawing 2 cards, enabling Dragonmaster Outcast way ahead of schedule.
On one hand, copying a single Overlord of the Boilerbilges for 3 mana with Devastating Onslaught already represents 4 damage twice and a 5/5 attacker, but a strong turn could imply having Enduring Courage and copying Threefold Thunderhulk 3 times (if you still only have 7 mana), then you would have 3 of them appear with 5 power, meaning another 15 gnome tokens with 3 powers and haste, and after attacking you'll get another 15 gnomes on defense.
If you have all those things exiled with Ghost Vacuum, you can pretty much do it out of nowhere for 6 mana.
In a pinch, copying a bunch of Enduring Courage could also do some damage since all copies would see each other and give more +2+0 haste triggers.
Fun fact, if you played a Threefold Thunderhulk, chances are next turn you will have the mana to activate Zookeeper Mechan on it to get a lot more gnomes out of it.
The sideboard includes 2 Meteor Golem because not much else still works well with Devastating Onslaught when there's an Authority of the Consuls in play, both as a powerful play and a way to get rid of it.
