mentioning what I added in the cuphead wiki would be too anachronistic, since Undertale didn't start production until 2013. cuphead started production in 2010. in other words, the latter's older than the former. QED
I'm not asking you when were they drawn, I'm asking you when were they published the first time and where's the source for that. If they were published after Undertale's demo there's zero chance of Flowey being inspired by that Cuphead character.
From the names actually on the cards, I is just called "Asriel" (even though it's his God of Hyperdeath form) and XIII is called "Absolute GOD of Hyperdeath" (even though this is his check text for his first form), Since they're Tarot cards, there's nothing "unofficial" about what they are, they're marked as Major Arcana I (The Magician) and XIII (Death).
KockaAdmiralac wrote: I didn't see anything official in the names "Major Arcana I (The Magician)" and ”Major Arcana XIII (Death)", where are these names used?
I also undid your revision before because you referred to Asriel's final form as "Absolute GOD of Hyperdeath" but I see you changed that now.
That's the names of those card numbers in the actual Tarot, see here for a brief rundown on how the Tarot deck works and here for a list, and this. is a decent list of what they're held to mean when used for divination. Since the cards in question aren't marked as minor arcana (ie the suits that became the modern playing card deck) they're Major Arcana.
The number at the top of each card in roman numerals, from 0-21, corresponds to a card from the list in the second wikipedia article I linked, and generally one with the equvalent theme (Mt. Ebott's card is XXI "The World ," for example, while Frisk is 0 "The Fool " and Chara (seen here on the left, it's not up on the wiki yet) XV "The Devil "). Since we know it's supposed to be a Tarot deck, these have to be the intended equivalents, it's like having a chess set: no matter what the eight things in the front row look like, you still know they're pawns. So having I at the top, Asriel is The Magician , while the XIII at the top means Absolute GOD of Hyperdeath is Death .
The one oddity with the cards is there's three "joke" versions of other cards: Sans and "Magma Hotsguy" are both XX (Judgement), Mt. Ebott and Return of Jerry are both XXI (The World), and Frisk and ICE-E are both 0 (The Fool). Given how they're shown here, I imagine the actual sequence is supposed to use Sans, Mt. Ebott and Frisk and the other three are just there for fun. I believe that tumblr post is the actual artist, who identifies the cards shown as the major arcana anyway. Here's the sequence from that tumblr post:
0 - Frisk / ICE-E - The Fool
1 - Asriel - The Magician
2 - Alphys - The High Priestess
3 - Toriel - The Empress
4 - Asgore - The Emperor
5 - Papyrus - The Hierophant (aka The High Priest)
The forum post has more and looks to include some minor arcana: the pictures in the Tarot card files category on the wiki I can give you, Mad Dummy is Ace of Swords, Lesser Dog is Page of Swords, Gerson seems to have taken over Gaster's role as The Hermit in the printed deck, and Burgerpants is the Page of Wands.
Found better copies of the remaining cards. Mostly more repeat major arcana:
Onionsan - Artist said Eight of Swords, even though there's no sword symbol on the card art they show. The printed version has one (see the forum post, you can just about make it out).
Bratty & Catty - Two of Cups
Bird That Carries You Over A Disproportionately Small Gap - Knight of Pentacles
Dogamy & Dogaressa - Another 6, The Lovers
Mettaton NEO - Another 17, The Star
Grillby - Another 19, The Sun
Stronger Monsters - Another 21, The World
The forum post also shows that printed 0 card for Frisk is now called "The Human," Return of Jerry's number box is blank (not even having a 0 in it, which means the deck has ditched Jerry), "Two of Swords" is now called "Doggo" in line with the other cards, ICE-E looks to be the something of pentacles and "Magma Hotsguy" looks like it's now the something of wands.