The text for Stalwart Shield indicates that it can only be cast on shields, but why not also allow it to be cast on a weapon? I don't think this would create a power imbalance, especially considering the difficulty of blocking packets with weapons. My guess is that this ritual was specifically created to give shields something cool and unique. Even if the ritual were allowed on weapons, however, a shield is still clearly the best target for the ritual, so I don't think it would take away from the unique relationship Stalwart Shield has with shields. While its use on a weapon may be niche, it would be cool as heck every time it's used.Stalwart Shield (General, Item [Shield], Passive) – When a Spell, Elemental, or Poison qualifier attack strikes a shield with this Ritual, the bearer may call "Resist" by expending a Strengthening charge as though the item were shatterable and hit by a Shatter effect. A Shield with this Ritual may be re-Strengthened by a Blacksmith to regain additional uses of this ability, unlike most enchanted items. Note that this Ritual still confers normal indestructibility as per other duration Rituals.