"Is Wearing Armor-inspired designs from non-muslim cultures kufr or shirk?"

According to Islamic law, it is permissible to wear or use something inspired by the armor or designs of non-Muslims or ancient cultures (like samurai menpo, kabuto, or elements such as the Gundam V-fin), as long as:

There is no belief of kufr (disbelief) or shirk (associating partners with Allah) in it.

It is not considered a religious symbol or an act of worship.

The intention is not to honor, imitate, or follow non-Muslims in their religion.

In this case, it is neither kufr nor shirk, and it is permissible, as long as the item itself is not forbidden in Shariah for another reason (like men wearing pure silk, or women wearing men’s specific clothing).

However, if that item is recognized as a religious symbol of non-Muslims, or it is used with the intention of honoring them, imitating their religion, or resembling them in a religious way, then it becomes impermissible (a sin). If it involves a belief of kufr, then depending on the situation, it could even lead to a ruling of disbelief and such serious matters are decided only by qualified scholars and muftis.

The basic rule in Shariah is that intention, belief, and the nature of the item (whether it is a religious symbol or not) are all considered together. Mere similarity in appearance or design does not change the ruling by itself unless there is a religious connection or intention behind it.

May Allah protect us all from kufr and shirk.

Aameen