On another day of making something out of nothing, I had the bright idea of trying to tackle Fusion Thunder. As my username would suggest, Thunder is one of if not my favourite monster types, and while there are decks in the metagame that use Thunder cards to great effect, they never are truly built around a majority of Thunder cards. Thunderbold, whose flagship monster is a Thunder, can be more accurately described as a either a Psychic or a generic pile deck depending on who you ask, and Executie Thunder, a less common Executie variant, only really uses Thunder cards because Sensor Duckbuill is Phoenix Dragons number 4-6. Digging deeper into the pool of just barely playables, we've got a large pile of just straight mediocrity. Thunderbeetle Storm was unironically in consideration for the best Thunder themed payoff, if it weren't for the fact that it couldn't kill Normal Monsters. Blitzkrieg Cavalry Triggerdrago is a weak attempt at mimicking Steel Mech Lord Mirror Innovator, Stormbolt Destroyer is in the pile of mediocrely statted monsters that summon extra tribute fodder, Poseigyon Advencharger just pumps all your on board Thunders by a small amount, and Showering Infergyo doesn't even impact the board, except in specific Level 8 matchups, which while admittedly are more common nowadays than before, the best deck this format is still a Level 7 strategy, so no points there. Overall, most Thunder cards aren't good. We're gonna try our best regardless to get this deck up and running.
Firstly for the 2 tributes, 3 copies of Blitzkrieg Cavalry Triggerdrago. This card isn't particularly good, it needs additional setup for it to start pressuring your opponent while they're on the backfoot (which we ended up not having the space for) but what's important is that it's a Level 7 Thunder, which allows it to be added to hand through Sensor Duckbuill, which we're running 3 of. I had considered running Multistrike Dragon Dragias in this slot as I had problems with kill pressure, but had no space to run Phoenix Dragon and thought it would be better to have the card of choice be fetchable from grave (among other Thunder synergies). What's more, Triggerdrago still has the niche of being able to beat over 2.5ks without outside help, unlike Dragias, and this is more important here as you'd need to jump through some hoops to beat over 2.5ks without something like Triggerdrago. We do want some way to force Triggerdrago's piercing effect when we need it, so the deck also runs 1 Card Devastation as a finisher. I've considered running 2 but the point of the card is to be able to capitalise off a winning position, and you need to be able to get to a position where you're winning for that to be good, so I cut it down to 1 copy. We're also running 2 copies of Stormbolt Destroyer for the last set of 2 tributes in the deck. Normally I don't really like these types of cards that summon tribute fodder and can't beat over 2.5ks on its own, but it allows you to fetch fusion material from grave and is a Thunder to add off of Sensor Duckbuill, so running some amount of it lets us access fusions easier. You could play a 3rd if you want to, the deck is quite light on 2 tributes after all, but in testing there were times where Stormbolt Destroyer just wasn't doing anything (one example is on the first turn where it's effectively a 2.4k pseudo vanilla), especially when facing down several 2.5k bodies, so we're only on the 2. Being lighter on main deck 2 tributes is theoretically fine since the fusions are also the main attackers in the deck. We also have 2 copies of Zapzap Octospark as the only 1 tributes in the deck. This is here as fusion material for Showering Infergyo, the card itself is awful but the 400 burn does come up sometimes. I don't want to run 3 of this as the card and fusion aren't that worth it, but it's still another fusion to make so some amount of it is nice to have and it's useful for some lethal lines.
As for low levels, we're running 3 copies of each of the fusion materials, Jellyplug, Anglercoil and Surge Bolt Lizard. Jellyplug doesn't have great stats but the others are 1.5k ATK beaters which isn't too bad. That statline is also important for Splitter Slime, which we're running 3 of alongside 1 Abyss Soldier, which is the legend card for the deck. The deck doesn't have particularly strong plays, comparing it to top tier strategies, so I chose a legend that could increase the number of high impact moves the deck can do as opposed to a more consistency oriented one like Graceful Charity, and the deck is already incidentally running a fair number of WATER attribute monsters (a lot of the fusion materials just happen to be WATER) so it's a good fit. Mirror Force or Torrential Tribute are possible options here, but Abyss Soldier is more proactive which is what I feel the deck needs more. It also lets you use Splitter Slime to its full effect, and having some kind of debuffer helps Stormbolt Destroyer or other monsters beat over opposing threats easier. Anglercoil and Surge Bolt Lizard happen to have an advantageous statline for Splitter Slime's effect, so it's a pretty good fit. We also have the aforementioned 3 copies of Sensor Duckbuill, which can fetch fusion materials either by grabbing an Octospark or through Stormbolt Destroyer's effect, or can just grab a decent beatstick. It also happens to be a WATER and can be discarded for Abyss Soldier. Since both Stormbolt and Octospark are also WATER, Sensor Duckbuill can convert any card in your hand into a WATER monster to be discarded for Abyss Soldier. As for other generics, 3 copies of Amazing Dealer for that consistency, especially nice to have for Fusion decks since they want to find multiple specific pieces. It also has a fusion of its own that comes up rarely, but still worth remembering, and is a WATER as well. Finally 3 of The Strange Specter of Celestial Severance as another consistency tool, filtering through the deck for specific things you want in grave like Sensor Duckbuill targets, Abyss Soldier for Splitter Slime or fusion materials to bring back with other cards. While it isn't WATER, there's enough other WATERs at this point for Abyss Soldier.
As for Spells, we've got the prerequisite 3 Fusion, and 2 Star Restart. Star Restart is a very strong piece of Fusion support that both fetches fusion material and the fusion spell itself. 1 Card Devastation as a finisher and 1 Dolphin's Treasure Chest for additional consistency. These 2 slots are basically flex slots, you could run 2 Dolphin's Treasure Chest or slot in the 3rd Star Restart or other things. Dolphin's Treasure Chest is fairly good especially when most of the deck is WATER monsters, but I wanted the space for other cards over the consistency tool, though honestly I'm still messing around with these slots myself. Namely 3 copies of Crisis at the Sacred Tower. This is an incredibly strong card, it's mainly for the Thunderbold matchup where the tribute summon of Thunderbold is very important to disrupt, but in general it's nice to disrupt practically everything since most decks will be tribute summoning. You could cut 1 of the Crisis for something else like a different trap, but with Thunderbold being at the forefront of the metagame, running the best trap into the matchup is a good idea, though building with less duplicates for Sea Dragon Knight is a viable option. 1 copy of Electrical Discharge is also in the deck, mostly here as a target for Surge Vortex Dragoon, one of the fusions, but it can be pretty nice especially into Secret Order, debuffing by 800 is a magic number with a 2.5k ATK monster or bigger since it stops attacks of 3.2k or smaller, which is what Secret Order reaches at max.
Lastly, the fusions. These are all going to be at 3 (not like you're running anything else anyway). Poseigyon Advencharger is your bread-and-butter, the easiest fusion to make. It's not all too impressive, buffing your Thunders by 400 ATK, but it does help Stormbolt Destroyer beat over 2.5ks and can pump Triggerdrago to 3.2k. Showering Infergyo is the one you make the second most often, and the 800 burn is one way for the deck to finish a game (if a bit gimmicky). Surge Vortex Dragoon and Splendid Floor Master aren't ones you go into very often, if they come up they're nice, but you shouldn't focus on making these every game. Dragoon comes up if you have nothing else you can do since it's statline isn't great, but resetting an Electrical Discharge isn't bad. Splendid Floor Master will barely come up since its materials are 2 of the same effect monster, but when it does come up the 1 or 2 draws aren't bad to have.
Overall, the deck still isn't good. It suffers from their tools just being incredibly mediocre. It doesn't help that Barrier Statue of the Inferno is in the format which shuts down your extra deck plays. But there are some fun plays that the deck can do if it finds its pieces, namely with Showering Infergyo for burn lethal plays. If you're looking to play a Thunder-focussed deck, this is probably the deck for you.