Gachanko Gachirobo's deck type focuses on the titular card, Gachanko Gachirobo itself. The deck is built around a certain mana cost - in this case, 7, hence 7-axis - to allow Gachanko Gachirobo's effects to go off. Gachanko Gachirobo allows you to play out your creatures for free from the top 3 cards of your deck, if they are the same mana cost.
The existence of Twinpact cards means that it is highly possible to play the deck with ONLY 7 cost cards (with the exception of Gachanko Gachirobo himself, who costs 6).
Cards like [R.S.F.K / Allin Charger] as well as [Ichigotchi Tank / Let's Goichigo] allow you to draw and ramp on the spell side, while providing a powerful finisher on the monster side.
Let's find out if the cards in the deck are worth the inconsistency of playing around 7-axis as compared to 6-axis!
Leledy Ba Gooba/Twinpact Map
Shield Trigger that can effectively take out one of your opponent's creatures that has power below it. Twinpact side lets you fish for other Twinpacts, like Ichigotchi Tank/Let's Goichigo or R.S.F.K/Allin Charger.
Stegoro Kaiser/Purification Sharrup
Creature side allows you to replace mana in case you accidentally charged a key piece, while having Mach Fighter to take out your opponent's key units. Spell side locks your opponent out of graveyard combos, which is very important in the Jashin matchup.
Ichigotchi Tank/Let's Goichigo
Creature side is a T.Breaker beater. Spell side allows for mana acceleration which is important for a Gachirobo deck.
R.S.F.K/Allin Charger
Funnily enough, also a finisher. R.S.F.K allows for potential World Breaker shenanigans as long as you win Gachinko Judge. Allin charger is a free draw and mana ramp against decks with many small cost units.
Alright, you've played your starting hand out now. You're on 6 mana, it's time to Gachanko Gachirobo!
He's 6 cost, and he checks the top 3 for cards that cost the same. If they all cost the same, it's free creatures on the field.
His other effect also allows your water creatures to not be attacked or blocked if your opponent has 2 or less shields.
What can you fish out with him in this deck?
Practically everything else, since it's a 7-Axis deck.
Some extender examples below.
Bolbazak EX
He's in the Hall of Fame for good reason. He untaps all your mana zone cards when he's put onto the field, allowing you to extend your combos with other cards.
King Manifest
Another combo extender, he allows you to play a card from the top of your deck. As the cards in this deck are all very powerful 7-axis cards or Gachirobo himself, a free card to play is always good.
Holyend, Destiny Dragon Armored/Now or Never
Master Spark with a body? Yes please. Spell side allows you to put a creature onto the field and bounce it back to hand, so it's great for using its creature side or even dropping Gachirobo himself!
DOOOPLER Macule
A powerful combo extender, it taps an opponent's creature when you put it in the field. Magibomber 7 allows you to extend your plays even further!
There are no combos to really write home about in the deck, since it's really just
Play Gachanko Gachirobo
Pray for top deck units with no Gachirobo in them.
Use whatever effects your units have.
If you need to push for even more plays, some of the units to support it are as follows:
Redgirazone, Roaring Revolution
Revolution Change allows for extended plays from your board. A very powerful creature which also untaps all your cards on Final Revolution and gives your commands Speed Attacker, Mach Fighter and can't be blocked.
XXDDZ Concatenated Awakening
EX Life allows you to secure one more shield. Gives your commands Speed Attacker and Slayer, while also having the ability to dump its own EX Life shield to stop all spell casts from your opponent next turn.
Medicalar Cobalt Kaiser/Eyed Wise Shutter
Want to not let your opponent play cards? Play this. Making your opponent's creatures not be able to attack, while drawing when they cast spells? Yes please. Spell side has Doran Gorghini's on play effect.
XXDDZ and Medicalar both impose restrictions on your opponent's plays, so you get extra annoying and ruin their plans.
Redgirazone is a powerful finisher to have, but do note that since you only have 1, you probably want to not rely on it too much as a game finisher.
Just stick with R.S.F.K and pray your opponent's deck has no cards higher than 7, and you're good to go!
7-Axis may not be very meta, but it sure will be satisfying to see the effects go off!