Gishki recieved 4 new pieces of legacy support in PHHY and they are all really good. Gishki now have the ability to set up Turn 1 boards with interruptions rather than just existing as a gimmicky handloop Deck. This is a pure Gishki Deck that uses the new Gishki support. At the very least, your Turn 1 board will have 2-3 monster negates, I:P Masquerena, 2 to 4 cards in hand and proper follow-up.
For our monsters, we play 1 Gishki Zielgigas, 2 Evigishki Nereimanas, 1 Evigishki Gustkraken, 2 Gishki Abyss, 3 Gishki Shadow, 3 Gishki Vision, and 3 Grim Gishki. Zielgigas is a massive 3200 ATK body that allows you to pay 1000 LP to draw a card and spin a card on field if the card you drew was a Gishki monster. While you won't be Summoning him Turn 1, he is still good Ritual fodder for the new Level 10 Gishki Ritual and he can net you advantage on Turn 3 onwards. Nereimanas is the new Gishki Ritual from PHHY and it is extremely good. On Ritual Summon, it can revive any WATER monster from GY including another copy of itself and it is not once per turn. Also, it can negate a monster effect and shuffle it into the Deck by returning a Gishki Ritual Monster you control to hand as an effect rather than cost and it is a soft once per turn. Not only can this card allow you to put up multiple monster negates if you Summon multiples, it also gives synergy with another card called Aquamirror Illusion which can Summon back the Nereimanas you returned to hand for another monster negate. Gustkraken on Ritual Summon looks at 2 random cards in your opponent's hand and you shuffle one of them back into Deck. This card is more of an additional play that you can make going first since this card aims to make a board rather than handloop. If you want, you can replace it with a 3rd Nereimanas since the possibility of Summoning a 3rd is definitely there. Gishki Abyss searches any Gishki with 1000 or less DEF on Summon which is not once per turn. This basically searches everything in your Deck aside from Nereimanas, so if you can keep Summoning it over and over again, you can search a ton of cards. You will usually be using it to search Gishki Shadow and Gishki Vision. Both can be an entire Tribute for a WATER Ritual Monster and they can discard themselves to search a Gishki card which is not a once per turn. Shadow discards itself to search a Gishki Ritual Spell while Vision discards itself to search a Gishki Ritual Monster. Both of these cards are insane and with them not being once per turn, you are able to search out the necessary cards to Ritual Summon as long as you have copies of them in hand. Grim Gishki can also be used as an entire Tribute for a WATER Ritual Monster and it can Summon any Gishki monster from Deck on Summon. This basically gets you to Gishki Abyss making it a starter and somewhat of a 1 card combo starter.
For handtraps, we play 1 Nibiru, the Primal Being and 3 Ash Blossom. Ash is good in general, but it and Nibiru are in here as Crossout Designator targets since this Deck is very subseptible to handtraps and disruptions.
For Spells/Traps: We have 1 Gishki Photomirror and 3 Gishki Aquamirror. Photomirror Ritual Summons by paying 500 LP for each Level on your Ritual Monster. While this means that you will be paying 5000 Life Points to Summon Nereimanas, not having to Tribute monsters is really good for conserving resources. Aquamirror is a normal Ritual Spell for the archetype and it can shuffle itself into Deck from GY to add back a Gishki Ritual Monster in GY which is good for recycling. We are not playing Gishki Icemirror as we are already using up 5000 Life Points for Photomirror, so Icemirror dealing DMG to you equal to the Ritual Monster's ATK is pretty bad considering it can either kill you or put you in a very precarious situation. However, it is still a good card for the archetype since its 2nd effect works well with Zielgigas. 3 Aquamirror Focalization. This searches any Gishki Monster and it can banish itself during the End Phase to set any Aquamirror Spell/Trap from Deck or GY. Not only does it provide more consitency, but it gives access to Aquamirror Illusion which synergizes very well with Nereimanas as I explained earlier. 1 Called by the Grave and 3 Crossout Designator. To reiterate, this Deck is very subseptible to handtraps and disruptions, so you need to protect yourself against those as best as you can. 3 Pot of Prosperity for more consistency. 3 Salvage which is like a godsend in this Deck. It basically adds back Shadow and Vision from GY which nets you more resources. And since it is not once per turn, you can amass a ton of resources if you have multiples in hand. 3 Infinite Impermanence for disruption, but it is also a Crossout Target. 1 Aquamirror Illusion. This card is good for reasons that I have already explained and Focalization can set it from GY so you only need to play 1.
Extra Deck only requires a few necessary monsters for your combo, so the rest can realistically be filled with anything of your choice. I am playing 1 Divine Arsenal AA-ZEUS - Sky Thunder, 1 Downerd Magician, and 1 Sky Cavalry of Centaurea. This is just a small Zeus package. You can also play Superdreadnought Rail Cannon Gustav Max and Superdreadnought Rail Cannon Juggernaut Liebe since this Deck can make Rank 10's, but I would rather not use my Ritual Monsters for Xyz Materials. 1 Herald of Pure Light and 1 Gigantic Spright. These are very playable Rank 2's in this Deck with Pure Light being able to add back a monster from GY and Gigantic Spright being able to do something like Summon a Gishki Abyss from Deck at the end of your combo to search follow-up. 2 Elder Entity N'tss and 1 EvilTwin's Trouble Sunny as Ultimate Slayer Targets. 1 Accesscode Talker and 1 Mekk-Knight Crusadia Avramax. Avramax could realistically be any Link-4 you want to you into with I:P. 1 Knightmare Unicorn and 1 I:P Masquerena. And finally, 1 Marincess Coral Anemone and 2 Spright Elf. Elf can be made with Abyss and Grim and then it can Summon back the Abyss for another search. After your first Nereimanas Summon, you will have 2 extra WATER monsters on field which can be used to go into Anemone to Summon back Abyss again for another search.
Side Deck consists of 1 Nibiru, 3 Ghost Ogre, 1 Effect Veiler, 1 EvilTwins Ki-sikil & Lil-la, 2 Cosmic Cyclone and 1 Harpie's Feather Duster, 3 Ultimate Slayer, and 3 Dark Ruler No More. If you think that Cosmic is a bit much considering that you've already paid 5000 LP with Photomirror, Twin Twisters also works. Also, Veiler is only here as another Crossout target, but it can be changed for any relevant handtrap in the current meta that severely hurts this such as something like Droll & Lock Bird.