Is it a sin to look at hentai/cartoon porn? What does the Bible say about hentai?

from the old testament

• Proverbs 6:25 warns against the seductive allure of lust and the danger of letting it take hold in one’s heart. The Old Testament consistently warns against lust, emphasizing the need for self-control and the dangers of letting sinful desires dominate one's heart (Proverbs 11:6; Ezekiel 16:26, 36).

from the new testament

• The impact of watching hentai damages our witness to others. Jesus taught, "Let your light shine before others, so that they may see your good works and give glory to your Father who is in heaven" (Matthew 5:16).
• Jesus specifically taught that a person who lusts commits "adultery in his heart," making it equally sinful with adultery (Matthew 5:28). While sexually immoral thoughts and adultery may result in different consequences in the eyes of people, both actions are sinful to God.
• Children of God that struggle with an addiction to hentai are not alone in their battle. We have the Holy Spirit living within us (Romans 8:9-11), so we can lean into His power and influence as we seek to put to death lustful practices in our life.
• Christians should recognize that our freedom in Christ means we are not enslaved to anything, including hentai: "'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" (1 Corinthians 6:12).
• The Holy Spirit sets Himself against our fleshly desires and leads us into righteousness (Galatians 5:16–18).
• Christians are called to flee sexual immorality (regardless of form) and live in a manner worthy of their new life in Christ (1 Corinthians 6:18).
• In Philippians 4:8, the apostle Paul says, "Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things." While rejecting worldly, ungodly content like hentai is certainly important, we must fill our mind with Christ-honoring thoughts.
• In Colossians 3:5, Paul communicates to believers that we have the ability to “put to death” what is earthly, which he identifies as “sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry.” If we are users of hentai, we must confess our sin to God and rely on His power to help us “put to death” this practice or addiction in our lives.
• As the apostle Peter taught in 1 Peter 1:14-16: "As obedient children, do not be conformed to the passions of your former ignorance, but as he who called you is holy, you also be holy in all your conduct, since it is written, 'You shall be holy, for I am holy.'"
• 1 John 2:16 says, “For all that is in the world—the desires of the flesh and the desires of the eyes and pride of life—is not from the Father but is from the world.” Hentai is undoubtedly a worldly form of entertainment that feeds our fleshly desires.

implications for today

Hentai comes from the Japanese word for "perversion" and refers to cartoon-based pornography. Originating in Japan, hentai is the outgrowth of anime (Japanese-styled videos) and manga (Japanese comics) with the addition of explicit adult content. Hentai is intentionally designed to cause real men and women to think about sexual ideas in ways outside of God's design. Whether cartoon or not, the same motivation is targeted—human lust—which is a sin. Hentai, like other forms of pornography, must not be a personal choice for the Christian. It dishonors God, hurts one's own walk with God, diminishes one's witness for God, and can harm relationships with a current or future spouse and family members.