Superheavy Samurai Prodigy Wakaushi - Maliss / Mitsurugi

This deck is designed around comboing into established boards by using board breakers and using the deck master, Superheavy Samurai Prodigy Wakaushi, to combo without using the normal summon and offering a free Pendulum Summon. So, if the combo is disrupted, there are still other options to continue.

From Superheavy Samurai Prodigy Wakaushi, you can do the full Mitsurugi combo (using King of the Feral Imps), and then the Maliss combo (using Code Igniter, which searches and summons Cyberse Code Magician). Any two Level 4 monsters can reach both of those combos, and with Cyberse Contract Witch you can also add Ame no Habakiri no Mitsurugi, so your pendulum summon can also help you reach those combos if Superheavy Samurai Prodigy Wakaushi is interrupted.

Alternatively, you can also use Superheavy Samurai Prodigy Wakaushi to do a small Sky Striker combo to protect your other plays if you have starters in hand like Ame no Habakiri no Mitsurugi and Maliss Dormouse. Sky Striker Ace - Camellia sends Sky Striker Mobilize - Engage!, which adds Sky Striker Mecha - Widow Anchor or Sky Striker Mecha - Hornet Drones, and then you can summon S:P Little Knight.

The chance to draw at least 1 board breaker (including Kaijus) in your starting hand + draw is 60%, without considering the card draw effects and the searches you can do to increase your chances while baiting interactions.

Main combo: https://www.masterduelmeta.com/combo/6a9caac33983111f093a9a1e

The endboard consists of 10 interactions and 4 follow-up/protection effects:

Every turn (6): 1 non-target banish, 1 targeting banish, 2 bounces (at once), banish up to 3 cards in any graveyard, 1 hand rip (or negate), draw 1, reborn 1 reptile every summon.

Only once (4): destroy all monsters any opponent controls (once per turn, 2 times), 1 omni-negate, 1 link summon using a link monster from 1 opponent, 1 non-target banish, 1 targeting banish, reborn 1 reptile.

If you have Decode Talker Integration and Firewall Dragon Singularity on the board, the OTK should be simple to achieve, even against 3 players.

Alternatives:

Superheavy Samurai Soulpiercer 

Prototype Sky Striker Ace - Amatsu 

Union Carrier, Dragon Buster Destruction Sword: Floodgate.

I:P Masquerena 

Firewall Dragon Darkfluid - Neo Tempest Terahertz, Cyberse Desavewurm, Danmari @Ignister 

You can choose to run I:P Masquerena instead of Decode Talker Integration, so that you can have an extra negate on one of your opponent's turns with W:P Fancy Ball. Or you could also run Firewall Dragon Darkfluid - Neo Tempest Terahertz (there's more than enough bodies to summon it, but it requires more Extra Deck space).