Triple Triad has its quirks

[Felis]

no i have a total of 18 cards and i get the same issue it will not let you put in more than 1 2 star, 3 star, 4 star, or 5 star card in your deck you are only allowed to have 1 of those cards with 4 1 star cards to make your deck where as all teh npc's can have any card combination there is and 90 % of the npc's have all the power house cards such as bahamut, odin, ifrit, titan. ramuh, ultima weapon ... its almost impossible you you have a 1% chance on actually beating one of these npcs and gor help you get an npc that has only random rule cause randomly your cards will be the crapiest you have in you collection where as teh npcs do not have the crappy cards at all they only carry the good cards there as they only get good cards out of a random draw..

You need 30 cards, not 18 cards
And 1 rare card is all what you need to beat a NPC with the Plus rule. And math of course.