While the Bible does not speak specifically about Pokémon or Yu-Gi-Oh!, or card/video games in general, it does give guidance on how we spend our time and what we allow to influence us. In 1 Corinthians 6:12, Paul says, "‘All things are lawful for me,' but not all things are helpful. 'All things are lawful for me,' but I will not be dominated by anything." Every Christian can rely on the Word of God and the Holy Spirit for guidance, and often, what is permissible for one Christian may be harmful for another. We should excise and avoid things in our life that are harmful to us, but we should be wise about our decisions. We are also called to be good stewards of our money and, so, should carefully consider the value of what we are spending it on.
There is no obvious, blatant immorality in Pokémon or Yu-Gi-Oh! games. However, there may be some cause for concern. With Pokémon and Yu-Gi-Oh!, the components most cited as possibly harmful are magic, Eastern spirituality, and gambling. Both Pokémon and Yu-Gi-Oh! are based in fantasy worlds, where combat and competition between monsters involve elements of magic. Players collect cards, or representations of cards online, and use them to battle other players and gain even more cards. It takes skill and luck to win. And money. Both the computer-based games and the card-based games can rack up expenses quickly.
In Pokémon ("pocket monster"), the player collects creatures, trains them, then uses them against the creatures of other players. Some creatures can evolve into larger, more powerful versions of themselves. Each creature has a set of strengths and weaknesses, plus a special magical ability. Some of the abilities are spiritual in nature and stem from Eastern faiths (Buddhist and Shinto traditions notably), such as psychic ability, possession, chanting, and communing with spirits.
Some Christians warn against allowing children to play Pokémon, though it is aimed at children, because it can be seen as introducing them to magic, evolution, Eastern religions, and even the occult. The gambling nature of the game can also be a concern. Parents should seek wisdom on this as to what effect such a game would have on their children.
In Yu-Gi-Oh!, aimed more toward young teenagers, a good-vs-evil storyline runs through the game, based on Japanese manga comics. The themes are more mature, and the content could be considered more disturbing. In Yu-Gi-Oh!, a spirit possesses the central character and drives him to take part in games of chance—gambling. Both the possession and gambling are a concern, spiritually. Part of the game involves negotiating with spirits, summoning, and such. The magic is more occult-like and the creatures more monstrous than in Pokémon. The game is more mature visually, narratively, and spiritually.
The complexity of the games goes beyond this article, so research is required if you or your child are getting into Pokémon or Yu-Gi-Oh!. Both games have elements that are concerning, to some degree. Neither game is blatantly a significant threat, nor can we outright conclude they should be banished from every Christian household. Gather the information, seek the wisdom of God, and continue to seek godly guidance. Remember also that the games have changed over the years. Both have made the spiritual and violent aspects of the game more secondary.